This PDF file contains the front matter associated with SPIE Proceedings Volume 7848, including the Title Page, Copyright information, Table of Contents, and the Symposium and Conference Committees listings.

We propose quantitative investigations of the Fabry-Perot resonance condition for the field enhancement by an isolated subwavelength metallic groove. The resonance condition is obtained from a simple Fabry-Perot model. Our calculations show that the electric field near the groove mouth that contacts the specimen is drastically enhanced under the resonance condition but is depressed out of the resonance condition. Giant electric-field enhancement can be obtained for narrow groove, which reveals nearly 10⁸ magnification of Raman signals. A weak dependence of the electromagnetic enhancement on the metal type is presented and explained.

Many studies on luminescence enhancement by surface plasmons were reported, among which metal nanoparticles were paid many attentions to, because of their special optical properties. The localized surface plasmon resonance can be tuned by changing nanoparticles' size, shape, interparticle spacing, and dielectric environment. They can be used for altering the optical properties of luminescence materials, and are used in the rare earth (RE) ions doped materials. For the RE doped materials, according to the Fermi golden rule, the spontaneous emission rate from excited level |i> to lower level |j> is Γ_ij∝|Μ_ij|²ρ(ν_ij),where M_ij is the matrix element related to the two energy levels, ρ_ij is the optical density and is also known as the photon mode density (PMD). In the present work, we experimentally demonstrated the influence of silver and gold metal nanoparticles on the luminescence of Eu complex. These nanoparticles had different sizes and shapes, including the silver spheres, nanoprisms and nanocubes, and gold nanoprisms. Based on the luminescence, lifetime and nanoparticles' absorption measurement, the different luminescence enhancement was obtained. The enhancement of luminescence had a great relationship with the overlap between the nanoparticles' localized surface plasmon resonance bands and the emission or excitation wavelengths. Their influence on the lifetime were also different, which meant the different infuence on the radiative and non-radiative decay rate. We further confirmed that the different influence of these nanoparticles partly came from the variation in the photon mode density (PMD).

The extraordinary optical transmission (EOT) through a subwavelength metal double-slit structure is calculated to study in detail the correlation between the single-slit and inter-slit effects on the transmissivity. A transmissivity formula is put down which retrieves the numerical results from the finite-difference time-domain simulation method. After some reasonable approximations made, the formula is expressed as the product of two periodic functions, determined by the length of a single slit and inter-slit distance, respectively. This simplified form shows that the interplay between the single-slit and inter-slit effects is almost negligible.

We will discuss methods to generate spatially collimated beams from surface plasmon polaritons. The representative method discussed in this paper is coupling surface plasmon polaritons, which are excited on a metal surface from a subwavelength metal slit, into collimated radiating fields with the use of surface gratings attached on the metal surface. In addition, the beam manipulation method by using multiple metallic waveguides, in which each waveguide has different width and length, will be discussed. With the aid of these methods, we will present three kinds of beams; on- and off-axis directional beams and a focused beam.

A new technique is proposed, in which a phase-shifting algorithm utilizing the optical Doppler effect and a high-speed CMOS camera are employed. In many phase-shifting algorithms, the phase distribution of the object is calculated by using a few reference phases with equal phase difference. In our proposed method, a reference mirror is moved continuously or randomly to make phase shift based on the Doppler effect. The phase distribution of the object is calculated by Fourier transforming the time-depending interference fringe data. If the reference phase shift is equally introduced to all the data points in the interference fringe image, the phase distribution at the peak frequency component in the Fourier spectrum gives the phase distribution of the object. Since a few hundred or more images were required in this method, a CMOS camera with a high frame rate of 500fps was used.

Three-dimensional information encryption based on the phase extraction and phase shifting interferometry is proposed. The three-dimensional information with the pure amplitude and pure phase are constructed as the encryption target. First the complex amplitude of the three-dimensional information is calculated under the scalar diffraction theory, and its phase distribution is extracted independently. Then it is encrypted by the double random phase encoding, the complex amplitude is recorded by using two-step of phase shifting interferometry. Computer simulations demonstrate the feasibility, the robustness and the security of the proposed method. We analyze and simulate its resistance against the known plaintext attack as well. Furthermore, it is implied the potential of applying this method for the three-dimensional information encryption with much larger information quantity.

In order to measure the 3D architecture of tire size code, Digital Speckle Pattern Interferometry (DSPI) and Phase Shifting interferometry(PSI) were integrated to capture its phase. With capturing speckle pattern interferogram by reference-wave interferometry, the illumination laser diodes of DSPI-PSI interferometer were arranged to enlarge the illumination area; and the viewing field was also expanded by battery of lens containing field lens and imaging lens. To generate a phase difference associated with height of test surface, the illumination beam was rotated by motor. The experiment results show the viewing field was more than 60 degree, the resolution of surface profile match the tire size code height as 1mm.

In this research, the feasibility of moiré deflectometry for diagnosing the temperature and the electron number density of rocket exhaust plume is studied. The dependence of the refractive index on the temperature, the pressure, the composition and the probe wavelength is established firstly. Based on which, the theoretical analysis and discussion indicate that it is impossible to achieve the measurement of the electron number density by both one- and two-wavelength moiré deflectometry in the given temperature, pressure and probe wavelength regions. Yet, it may be feasible to measure the temperature distribution of rocket exhaust plume by moiré deflectometry, if the imprecision of the temperature reconstruction is permitted by the practical measuring requirement.

A polarizing color filter, combining the function of polarizer and color filter, is proposed and theoretically investigated. The proposed color filter comprises of a metal grating and a dielectric layer on a glass substrate. The influence of the geometrical parameters of dielectric layer on the transmission efficiency are discussed in detail by rigorous coupled-wave analysis (RCWA). The result shows that a dielectric layer of high equivalent refractive index can enhance its performance effectively. A optimum tricolor filter with more than 74.1% broadband transmission and a polarization extinction ratio of 8.39dB is obtained.For TE-polarized light, it is reflected and can be recycled in the backlight units to increase the total energy utility. The numerical result shows that the peak transmission efficiency can increase 21.5% by using the proposed devices.

In recent years, photovoltaic cells have attracted much attention and extensively been studied by many groups. The amorphous silicon (a-Si) thin film solar cells have the advantages of lower cost, less material consumption and potential for the building-integrated applications although the conversion efficiency is usually below 10%. In this paper, we show an a-Si thin film solar cell with periodical nanorod structures for light trapping enhancement and an ultrathin silver film as transparent electrode with a lower resistance for performance improvement. In such a design, the conversion efficiency can be greatly improved. The periodicity and duty ratio of the nanorods were optimized to enhance the diffraction of the light within 500-900 nm into guided modes in the a-Si thin film and thus the total optical absorption can be enhanced. Furthermore, a 5-nm ultrathin metal film was used as a transparent electrode to replace the conventional transparent conductive oxide while having a lower sheet resistance of 9.6 Ω/ and a transmittance from 90% to 70% within the spectral range from 300 nm to 900 nm. Our design was analyzed by using the full-wave finiteelement method to calculate the optical absorption of the incident sunlight in the a-Si thin film. According to the simulation results, the light absorption can be relatively enhanced by 69.6% and the total conversion efficiency can be relatively improved by 41.6% compared to the conventional thin film a-Si solar cell without nanorod structures.

The detection limit of surface plasmon resonance imaging (SPRI) biosensor is constrained in part by the SPR biochip and in part by the resolution of the optical intensity of detecting instruments. In this paper, silicon photodiode is proposed as the optical intensity detecting element instead of the traditionally used charge coupled device (CCD), combining with high resolution analog/digital converter, this method can efficiently reduce the cost and increase the sensitivity of the SPRI system while keeping its virtue of multiple channels real time detecting. Based on this method, An SPRI experimental system with two channels is designed and the optical intensity of each channel is detected by a photodiode. By carrying out testing experiments using sucrose solution with different concentrations (corresponding to different refractive index), the system sensitivity of 10^-6 refractive index unit (RIU) is obtained.

The metallic superlens of a single negative permittivity is easier to implement than the double negative material superlens and can be applied to nano-scale resolution lithography. The metallic superlens amplifies by the resonance the surface plasmon polariton (SPP) waves, which carry the sub-wavelength detail information of the object. However, the excitations of the long- and the short-range SPP modes of the metal slab lead to two peaks in the transfer function which enhance the spatial frequencies disproportionally, resulting in strong sidelobes in the image. Conventionally the metallic superlens is designed by trials without rules to follow. We propose to design the metallic superlens by approaching the cutoff condition of the long-range SPP mode in order to flatten the transfer function and to improve the imaging performance significantly. Design experiments of Al and Ag superlens with both the transfer-matrix approach and the numerical Finite Difference in Time Domain method are shown.

In this paper, we report the viscoelastic properties of sodium polystyrene sulfonate (NaPSS) solution with different concentrations (in the range of 10^-4 M to 10^-3 M) and with different molecular weights (70 kDa vs. 200 kDa) investigated via Diffusing Wave Spectroscopy (DWS). The viscoelastic properties of the sample solutions are characterized in terms of the elastic modulus G' and the viscous modulus G" as a function of frequency (f), and also in terms of the polymer disentanglement time (τ); the effect of polymer concentration and molecular weight on these parameters are presented. Our experimental results indicate that (1) both the viscous modulus G" and the disentanglement time (τ) increase with molecular concentration, whereas the elastic modulus G' is relatively insensitive to molecular concentration, and (2) for the same concentration, all the 3 parameters (i.e., the elastic modulus G', the viscous modulus G", and disentanglement time τ) increase as the molecular weight increases.

Two-dimensional (2-D) square lattice (SL) photonic crystals (PCs) are fabricated and their optical/electro-optical properties are studied. The PCs are based on polymer-dispersed liquid crystals (PDLC) that are formed using twobeam interference with double-exposures. The PC structure that is observed using a scanning electron microscope (SEM) matches with the calculated interference pattern. The results of optical/electro-optical studies demonstrate that superprism and negative refraction effects occur at certain incident angles over a range of frequencies, and are consistent with the simulated ones. Moreover, the negative refraction efficiency is electrically controllable.

We describe a simple, reliable, and reproducible fabrication technique for a high-order spiral phase plate with high power efficiency 86%. The performance of the fabricated Spiral Phase Plate (SPP) is verified by using vortex characteristics of fraunhofer and fresnel diffractions of a finite-radius plane wave, which is in agreement with the theoretical calculation result.

An encapsulated rectangular-groove fused-silica grating as a highly efficient two-port beam splitter is presented, which is designed at a central wavelength of 1550nm under Littrow mounting. The design method of such a high-efficiency two-port beam splitter grating is mainly based on the simplified modal method with consideration of two beam interference of the modes excited by the incident wave. Meanwhile, this encapsulated grating can be considered equivalent to an effective Fabry-Perot-resonator, therefore, Fabry-Perot interference of grating modes inside the grating area also plays an innegligible role in achieving high efficiency and equality in the diffracted zeroth and minus-first orders, which also should be considered in the design. The rigorous coupled-wave analysis(RCWA) is used to verify the design method and optimize grating profile. Numerical simulations show that, the RCWA results agree well with the design conditions derived from modal method. And with the optimum grating profile, high total efficiency(99.78%) and equal intensity of the diffracted zeroth and minus-first orders can be obtained at the wavelength of 1550nm. Moreover, the designed encapsulated beam splitter can work well over the C+L band and within 21° angular range. The encapsulated grating can exhibit higher diffraction efficiency, intensity equality and less reflection loss than conventional rectangular-groove grating.

For the laser spot size, the blazed diffractive grating fabricated with direct laser writing will has a slantwise lateral facet edge. To evaluate the influence of the slope of the facet edge of blazed diffractive grating, we calculate the diffraction efficiencies in +1 order and zero order as a function of the angle for the slantwise lateral facet edge with rigorous coupled wave analysis. As the lateral facet edge is getting more slantwise, the diffraction efficiency in +1 order decrease more, which degrades the image quality in monochromatic imaging. But the diffraction efficiency in zero order always keeps very low to assure the application in optical limiting.

Laser beam shaping is required in many applications for improving the efficiency of the laser systems. In this paper, the near field beam shaping based on the combination of simulated annealing algorithm and Zernike polynomials is demonstrated. Considering phase distribution can be represented by the expansion of Zernike polynomials, the problem of searching appropriate phase distribution can be changed into a problem of optimizing a vector made up of Zernike coefficients. The feasibility of this method is validated theoretically by translating the Gaussian beam into square quasi-flattop beam in the near field. Finally, the closed control loop system constituted by phase only liquid crystal spatial light modulator and simulated annealing algorithm is used to prove the validity of the technique. The experiment results show that the system can generate laser beam with desired intensity distributions.

Deep-etched fused silica grating is a kind of high density phase gratings whose surface are etched into an optimized depth for achieving a series of novel functions, such as high efficient diffraction at the -1 order, polarizing beam splitting, 1x2, 1x3 beam splitting, etc.. Since deep-etched fused silica grating is made of pure dielectric material of fused silica, so it has a high laser damage threshold for high power laser applications. We fabricated the polarizing beam splitter of the fused silica grating and realized the even and odd modes for analysis of fused silica grating. We gave the generalized equations for describing the performance of polarizing beam splitting and high efficient diffraction at the -1 order. We gave the analytic equation of 1x3 diffraction, which is impossible to obtain with the previous rigorously coupled wave method. For fabrication of deep-etched fused silica gratings, holographic recording, lithographic technique, and inductively coupled plasma etching are used to make the deep-etched gratings. Deep-etched gratings have a variety of practical applications. It can be used for demultiplexing optical signals in DWDM optical fiber communications. It can also be used as a pulse compressor of femtosecond or picosecond laser pulses. It can also be used as polarizing beam splitter, high efficient diffraction for spectrometer, etc.. Deep-etched fused silica gratings have a bright future for practical applications.

Large-size diffraction gratings are essential for pulse compressors in chirped-pulse-amplified high-power laser systems, spectroscopic telescopes, etc. Fabricating large gratings requires large-aperture laser beams with collimated and aberration-free wavefronts. As an alternative a method of making monolithic gratings by optical mosaic has been proposed, which makes multiple-exposures in different areas of a substrate to enlarge the grating size. Between exposures the position and attitude of substrate must be adjusted to minimize the overall wavefront errors, with very tight accuracy requirements (~ dozens of nanometers and tenths of micro-radians, respectively). We fully utilize the latent fringes (exposed but undeveloped fringes in photoresist) as the core reference object and the exposure beams as the adjustment beams to adjust and lock the position and attitude between consecutive exposures. This approach greatly simplifies the alignment system and eliminates many system errors. However, the diffraction efficiency of a latent grating is extremely weak (~10^-5) and excessive exposure of the latent fringes during the position and attitude adjustment should be avoided. We overcome these difficulties by carefully blocking stray lights and using a high-sensitivity CCD to monitor the interference fringes of the –1st- and 0th-order latent-fringe diffracted wavefronts. Experimentally we have made 2 x 2 mosaics of (60+28) x (53+30) mm² grating area. Typical peak-valley and rootmean- square values of the measured –1st-order diffraction wavefront errors are 0.06 λ and 0.01 λ, respectively. The mosaic conditions, detailed alignment steps, and experimental results showing position and attitude controllability will be presented. Important issues of extending the present work to large-size (possibly sub-meter) fabrication will also be discussed.

A projection photolithography method is presented in the paper, which can be used for fabricating continuous surface structure with the aperture of a few micrometers. In the method, a microlens array is used to form minified images of a designed object. When the parameters of the microlens and the object are properly determined, images with minification from hundreds to thousands times can be obtained. Photoresist is used to record the images and patterns with micro or sub-micro critical size could be manufactured. Both geometric and diffraction theory are used for optimizing the parameters and the design process is given. Resist reflow method is used in our experiment for achieving microlens array with the characteristics of a large NA and a small period. The micro-taper array with period 20 μm and aperture of 5 μm was manufactured with the method and the home made microlens array photolithographic system.

A compound-eye imaging system has been proposed in which the microlenses arranged in a convex solid substrate are designed for satisfying the requirement of both a large field of view and a flat receiving plane. Based on the geometrical optics, the formulas are established for determining the parameters of the microlens in the different positions so that the focal spots of the microlens array can properly be settled on a flat plane. With the method, ray tracing is carried out for simulating the focusing process of the compound-eye imaging system. The results show that the focal spots distributed on a plane are achieved and the field of view of the system can be up to 60°.

The convex grating is one of the key elements in hyperspectral imaging spectrometers. In this paper the diffraction characteristics of the convex blazed grating is investigated by using rigorous coupled-wave theory, which indicates that within the wavelength from 0.4μm to 0.8μm, the plus first-order diffraction efficiency can be over 35% through controlling the blaze angle of blazed grating. The convex blazed grating with the period of 5μm in the center, the blaze angle about 4.3 degree, and the ruled area - a convex substrate with its radius 72mm and aperture 35mm has been fabricated by holographic- scan ion beam etching. Experimental measurements show that the plus first-order diffraction efficiency is more than 35%, within the wavelength from 0.4μm to 0.8μm.

Micron-sized grating structures (MGS) and sub-micron sized dot arrays (DA) were generated on silicon target by multiple shots of interfering nanosecond laser beams. The mechanism to form MGS and DA were analyzed and it is found that the obtained structures have a negative shape of the interference pattern. The most major size of the periodic structure is 500 nm. The optical properties of these nanostructures are also investigated. The silicon DAs function as both absorber and antireflection layers, which offer a promising approach to enhance the solar cell energy conversion efficiency.

To compensate misregistrations between a detector array and a spatial light modulator in page-oriented volume holographic data storage, a method based on a three-pixel model is proposed against sub-pixel misalignment. Several methods for pixel mismatch compensation are reviewed. The quadratic two-pixel method is inapplicable when the local shift is negative or the size of the aperture is relatively small. The inter-pixel crosstalk model is revised and an improved three-pixel model is developed, which can be used to compensate arbitrarily misaligned data pages. The compensation method uses prior information of the pixels on the input spatial light modulator (SLM). Recursive solutions are carried out to recover the real values of the SLM pixels. Both simulation and experimental results show that the signal-to-noise ratio (SNR) can be doubled approximately by use of the compensation method based on the three-pixel model. The proposed method is appropriate for both positive and negative pixel shifts, and has similar effects of equalization, which effectively improves the SNR.

We summarize our theoretical study of the collinear volume holographic storage system. Simple formulas with direct physical concepts are developed under paraxial condition with scalar diffraction theory and VOHIL model, which are much helpful in figuring out the characteristics on point spread function (PSF) and the shift selectivity. Accordingly, effective system design is possible.

We record a reflection volume hologram with two plane waves in lithium niobate. By heating one corner of the LiNbO₃ crystal, it will cause an inhomogeneous temperature distribution in the crystal. The thermal expansion results in small slight deformation of the volume hologram and then decreases the intensity of diffraction light. We also use the model of volume hologram being an integrator of the lights emitted from elementary light sources (VOHIL) to calculate the diffracted field for the linear thermal expansion. The results of experiment and simulation are both shown that the intensity of diffraction light decreases from the heating corner of the crystal. The change of intensity of diffraction light is predicted successfully with the model of VOHIL for the thermal expansion.

Rewritable collinear holographic image storage was realized in a genetically mutated bacteriorhodopsin BR-D96N film by using its photochromic property. For a BR-D96N film with 3.0 optical density, under 632.8nm, 700mW/cm² recording light (optical reference ratio is about 1:1.2), the optimum recording time is about 3s, and optimum reconstruction light intensity is about 50mW/cm², and the safe-time of the hologram is about 10min. The experiment shows that, in collinear holographic storage system, simple optical setup, small volume, low environmental effect and the high density storage can be realized; and it is proved that the BR-D96N film has advantages like short storage time, high light sensitivity, high reversibility, long-term stability and easy used, which can be used as a high sensitive dynamic rewritable collinear holographic storage media.

In this paper, we report experimental results of measuring picosecond laser pulses using a second-harmonic generation (SHG) intensity autocorrelator. This home-made apparatus of the intensity autocorrelation is an attempt to measure the SHG pulse's intensity change with time. It is clear that an intensity autocorrelation can be used for measuring the pulse length of the ultrashort pulses laser. Using this SHG intensity autocorrelator, we measured the pulse length of a diodepumped picosecond passively mode-locked Yb:SSO laser which emits at a central wavelength of 1061nm at a repetition rate of 52MHz, and a mode-locked picosecond laser amplified system centered on 1064nm at a pulse repetition frequency of 1K HZ. Compared with the commercial autocorrelator, this setup has a larger measurement range, higher accuracy, and more reliable results. In addition, using a high resolution spectrum instrument the apparatus becomes a FROG. The full information of the pulse can be retrieved by using a frequency-resolved optical grating (FROG) algorithm. This setup should be very useful for further optimization of the diode pumped picosecond laser.

The focal shift effect and axial dispersion property of binary pure-phase filters (BPFs) in focusing systems are described in the regime of the scalar Debye theory. By expanding the formula of the electric field in focal region into a summation of a polynomial series, the axial behavior and the general rule of the focal shift effect of BPFs are analytically studied. The small focal shift formula of BPFs is derived based on the second-order approximation, and its scope of validity is also discussed. Based on this small focal shift formula, the property of axial dispersion for a given BPF is also analytically discussed. Furthermore, numerical results of 2-zone and 3-zone BPFs with various normalized radii and phase shift values are also given for verifying these analytical results. At last, as an example, the application of BPFs with negative axial dispersion in compensation of chromatic aberration of a single lens in an ultrashort laser focusing system is presented. The numerical results show that the chromatic aberration induced by the single lens is compensated well nearly for the whole spectral bandwidth of the ultrashort laser. Therefore, this focal shift effect induced by BPFs should be of great interest for its potential applications in compensation of chromatic aberration and compact tunable focal modulation in some special cases.

As one of the fiber-based wide-band promising components, high channel-count fiber Bragg grating has recently attracted great interests. In this paper, we introduce our recent developments in the design techniques for the ultra-high channel-count fiber Bragg gratings (FBG). The key technique is based on the utilization of a continuous phase-only sampling, which is the same as the one for the optimization of a phase-only grating in the diffractive optics. With the proposed sampling method, we have theoretically demonstrated a novel doubly sampled FBG with channels up to 405, which could be used as either the dispersion compensator or the comb filter in broad-band wavelength-division multiplexing (WDM) system.

Recently, the research on all-optical analog-to-digital conversion (ADC) has been extensively attempted to break through inherently limited operating speed of electronic devices. In this paper, we propose to use the photonic crystal fiber for time-stretch analog-to-digital conversion (A/D) system through generating low-noise, linear chirp distribution, flat super-continuum generation. Based on the RF analog signal modulation-to-line of chirped pulses, large dispersion photonic crystal fiber is used for time-domain stretching.

Although there are several well -known methods such as RCWA, FMM, for analyzing the diffraction properties of gratings, design of these optical elements with specified spectral properties is commonly a challenging problem. It is relatively not easy for the researchers to design narrow line-with diffraction filters based on guided mode resonance phenomenon with common diffraction algorithm. Simulated Annealing (SA) method is evolutionary, robust technique that has been widely utilized to design optical diffraction components. This method is inspired by the physical process of heating and controlled cooling of metal material to increase the size of its crystals and reduce their defects. The most distinctive features of this method lie in its powerful ability of convergence towards the global minimum in a reasonable computation time and the independence of the initial parameter values. In this paper, first, the physical basis of SA and its mathematical realization are introduced. Then, a Guided-Mode Resonant Grating (GMRG) filters with single layer is designed by using SA algorithm. The central wavelength of GMRG filter is locked at 532nm and its line-width is fixed at 1nm. The plane wave light radiates the grating from air cover with normal incidence. The optimized parameters are refractive indices and thicknesses of high and low material of grating, other parameters are grating period and fill factor of the grating. It is shown from our calculation that an excellent reflection spectrum with narrow line-width, high peak and low sideband can be obtained after optimizing the grating parameters. Next, a double layered GMRG filter with line-width of 4nm, which is relatively easy fabrication in experiment, is designed at central wavelength of 1064nm. The optimized parameters are grating period, groove depth, refractive index of waveguide layer and fill factor respectively. The grating substrate and waveguide layer are Sio2 and Hfo2 respectively, the grating structure is directly etched on the waveguide layer. The above grating values should be included in reasonable ranges in consideration of grating fabrication in our experiment condition. It is demonstrated from the calculations with the parameters obtained from SA optimization algorithm that the peak diffraction efficiency is more than 99% at central wavelength 1064nm and the sideband reflection is depressed at the level bellow 5% in a large wavelength range. Moreover, the parameters of a triple layer GMRG filter structure are also provided with this powerful method. Meanwhile, the results found by SA method are compared with RCWA theory.

This letter presents a method for real-time three-color digital holographic interferometry based on Foveon CCD. The control mode of CCD is optimized and color aliasing is limited consumedly. The influence on color hologram becomes very little. On the whole, color aliasing is eliminated especially in the phase difference detecting. Moreover, the optical setup is considerably simplified, since the reference beams are combined into a unique beam. Experimental results confirm the suitability of the proposed method.

A digital holographic method for evaluation of an inner surface profile of tubes is proposed. For surface contouring, two wavelength method using an injection-current induced wavelength change of a laser diode is used. To obtain the inner surface profile, a cone-shaped mirror is inserted into the tube. Distribution of an optical path length in the experimental alignment is calculated and utilized to compensate for a distortion occurring in the experimental profile of the surface due to a deviation of a mirror position. The shape of two seals pasted on the inner surface can be evaluated by the method with a digital image processing. It is shown that the proposed method can visualize and detect three dimensional shape of defects on the inner surface of tubes.

Integral imaging captures three-dimensional information of the object scene by sampling the spatial and angular distribution of the light rays. In this paper, we show several three-dimensional imaging techniques based on integral imaging. First, principle of integral imaging and its basic three-dimensional visualization methods are explained. Then as its application, a three-dimensional microscope is introduced. The three-dimensional information of the microscopic specimen can be captured by applying the integral imaging principle to the conventional microscope. An extension of the basic three-dimensional visualization is also explained to enhance the resolution of the arbitrary view reconstruction. Three-dimensional information embedded in the captured ray distribution can also be exploited to synthesize the threedimensional holography of the object, which provides an efficient way for incoherent holography capture. Finally, we show an analysis of the sampling of the ray distribution. By analyzing the spatio-angular bandwidth of the ray space, the optimum sampling strategy can be found.

A method for improving the performance of phase-only spatial light modulator (SLM) is proposed in this paper. For an electrical-addressed SLM, the pixelated structure just likes a 2D black-matrix. It will have an intrinsic effect on the incident light whether image is loaded into SLM. This inherent effect was called black-matrix effect characterized with zero-order diffraction of high brightness and high-order diffraction terms in the Fourier plane. This is strongly influenced the quality of phase modulation. In order to eliminate the black-matrix effect of SLM, a linear phase map or a digital Fresnel lens is compensated to the original phase map. The black-matrix effect will be separated with the reconstruction pattern in the perpendicular plane of the optical axis or along the optical axis. Therefore, the black-matrix effect will be eliminated through digital phase compensation. The theoretical analyze, computer simulations and experimental results are all presented to demonstrate the validity. Possible applications include almost all phase modulation applications.

In this paper, a method of measuring the phase modulation properties of spatial light modulator (SLM) by heterodyne interferometry is proposed. As a kind of key elements in the advanced optical information processing systems, spatial light modulators is widely used in many important fields, especially used as a dynamic phase modulating device. So, the phase calibration plays an important role in the SLM applications. Compared with the methods based on traditional interferometry, this method measures the phase response directly by taking advantage of the heterodyne mechanism, so it leads to higher accuracy. A heterodyne-interferometer based calibration system making use of acousto-optic frequencyshifters has been designed and realized. Theoretical analysis and experimental results demonstrate the validity of this method.

The wavelet transform with coefficients selection method and the one of traditional frequency domain filtering methods named Gaussian high-pass filter method are used for the reconstruction of the digital holograms in this paper. In order to eliminate the speckle noise near the filtered zero-order diffraction spots more effectively, the high and low frequency coefficients in the wavelet transform were adjusted. A holographic experimental system based on Michelson interferometer was set up and digital off-axis holograms were recorded. By adopting the Robert gradient method in Iconology, the reconstructed results both by the wavelet transform with coefficients selection method and the traditional Gaussian high-pass filter method were compared. The larger the gradient magnitude value (G) is, the more information the image contains, and the image is clearer. The G values of the reconstructed images got by wavelet transform with coefficients selection method and the traditional Gaussian filtering method are 1099891 and 1042562, respectively. The results validated that applying the wavelet transform with coefficients selection method for digital hologram reconstruction can more effectively eliminate zero-order diffraction image and improve the SNR and quality of reconstructed image than applying the traditional Gaussian high-pass filter method.

Phase unwrapping is an important content of digital holography, which gets continual and real phase from wrapped phase. The least-squares phase unwrapping is a fast and effective method. But for wrapped phases with complicated variation and much noise, the unwrapped phase got by least-squares method will produce errors. In this paper iterative unwrapping of phase difference is combined with least-squares unwrapping to eliminate the errors. This method is used in digital holography to unwrap phases with complicated variation. The phase variation of object wave through a polymethyl methacrylate (PMMA) specimen with a hole under uniform tensile force is measured by holography. The phase is unwrapped by phase unwrapping based on least-squares and iteration. The cosine patterns of unwrapped phase and wrapped phase are consistent. Which means this method is correct and can be used to unwrap phases with complicated variation and much noise.

In this paper a method of numerical recording and reconstruction a large size color holographic image by using of angular spectrums diffraction equation is presented. At first, the digital hologram of large size color object which is illuminated with differently wavelengths (red, green, blue) is recorded by a black-white CCD. Then each monochromatic holographic image is reconstructed with the same magnification, and the corresponding digital color holographic image is acquired by accurately synthesizing the reconstructed monochromatic images. In order to record the hologram of large size object, a negative lens is used; and wave-front of reduced image of object is recorded by CCD. At the same time, a good reconstruction image is achieved by eliminating zero-order image with Liquid crystal spatial light modulator (LC-SLM). The experimental results demonstrated that the method presented in this paper can preserve the high frequency information of the object very well, thus can significantly improve reconstruction image quality.

A optical system using concave lens, which is used to image a big object preliminarily, is presented. This is an applicable method in digital holography detection. Digital holography reconstruction is studied according to inverse calculation of Collins' formula and setup optimization for digital hologram recording system is presented. Theoretical study implies that using concave lens can make the recording system more compact. Further more, in order to make the system be suitable for multi-wavelength illumination, the focal length of lens is modified according to wavelength of irradiation, and the setup optimization is performed so as to record hologram successfully with multi-wavelength illumination. To valid this method, several holograms are recorded under dual-wavelength illumination with the setup and object fields are reconstructed through focus modification.

Nowadays, with the rapid progresses in flat panel display (FPD) technologies, the three-dimensional (3D) display is now becoming a next mainstream of display market. Among the various 3D display techniques, the stereoscopic 3D display shows different left/right images for each eye of observer using special glasses and is the most popular 3D technique with the advantages of low price and high 3D resolution. However, current stereoscopic 3D displays suffer with the 3D crosstalk which means the interference between the left eye mage and right eye images since it degrades the quality of 3D image severely. In this paper, the meaning and causes of the 3D crosstalk in stereoscopic 3D display are introduced and the pre-proposed methods of 3D crosstalk measurement vision science are reviewed. Based on them The threshold of 3D crosstalk to realize a 3D display with no degradation is analyzed.

A binary beam splitter and a color separation grating in Fresnel diffraction field are designed and analyzed by vector theory. The grating period of both gratings is around 1.5λ, in the range of λ to 2λ, to ensure three diffraction orders only. The diffraction behavior is analyzed by modal method, so that the field distributions of the propagating modes and the diffraction orders can be expressed. The first two even propagating modes are taken into account and the higher modes are neglected. Using the initial solutions given by the modal method, the exact design parameters can be obtained by RCWA without searching all the parameters. When the duty cycle is 0.5, the grating depth is 0.374μm and the beam splitting plane is chosen at 2.06μm, the energy efficiency of the 1:2 beam splitter with wavelength 0.6328μm is 64.3%. As the color separation grating for red color with wavelength 0.6328μm and blue color with wavelength 0.45μm, the color separation plane is chosen at 4.22μm. The energy efficiencies are 73.3% and 75.9% for red color and blue color respectively, and the color separation ratio is 0.9.

We propose novel depth-fused three-dimensional (DFD) method using polarization distribution, which is one kind of multifocal plane display that provides autostereoscopic image with small visual fatigue. The DFD method is based on the characteristic of human depth perception when the luminance-modulated two-dimensional (2D) images are overlapped. The perceived depth position is decided by the luminance ratio of each plane. The proposed system includes the polarization selective scattering films and the polarization modulating device. The polarization selective scattering film has the characteristics of partial scattering according to the polarization state and transmits the rest light from the scattering. When the films are stacked with the scattering axis rotated, each layer of film provides different scattering ratio according to the incident polarization. Consequently, the appropriate modulation of polarization can provide DFD image through the system. The depth map provides depth information of each pixel as a gray scale image. Thus, when a depth map is displayed on a polarization modulating device, it is converted into a polarization distributed depth map. The conventional twisted nematic liquid crystal display can be used as a polarization modulating device without complicated modification. We demonstrate the proposed system with simple experiment, and compare the characteristic of the system with simulated result.

To form a laser image, there usually are two kinds of image forming methods. One is to direct slender laser beams to special points by light directing element (LDE). The other one is light blocking method where amplitude spatial light modulator (SLM) used to form laser image. The former method has high light efficiency for none light is blocked, however precision mechanical instrument used as LDE is needed. In this paper, we describe a new kind of laser imaging method based on computational holography. Coherent light is used as source and phase SLM as LDE. The function of phase SLM is to change the phase of light illuminated on it. The light on the pixel will travel in new direction according to the phase change. Iterative Fourier Transform Algorithm (IFTA), also known as G-S algorithm, is used to find phase change value of each pixel. The process of laser image forming is simulated with VirtualLab™ and optical system is built to form the laser image. 2D and 3D image can be formed by the proposed method and they enjoy the advantages of laser display, such as full color gamut and sharp intensity.

A novel method for reconstructing polarization distribution of an incident light beam is proposed. Detected light beam is incident on a proposed optical measure system and then is divided into two paths of light beams by a splitter equably. Two wave planes are imaged on two CCD sensors through two imaging lenses respectively. In front of the two CCD sensors, two groups of polarization optical elements are placed, including wave plates, birefringent wedge prisms and analyzers. Through these optical elements, wave functions are modulated and recorded by two CCD sensors. Through Fourier transformation and inverse Fourier transformation of intensity distribution recorded by CCD sensors, and according to the proposed algorithm, polarization state distribution of the incident light beam can be determined. Numerical simulation proves that the proposed method can reconstruct polarization state of a light beam effectively.

The strong lateral polarization component of radially polarized beam focused by high numerical aperture objective shows totally axis-symmetrical property, which gives rise to its widely applications in many optical devices. The equations of vectorial three dimensional(3D) electric field of radially polarized beam focused by high numerical aperture objective are given based on the vectorial Debye theory. The finite difference time domain(FDTD) method is applied to simulate the focusing of radially polarized beam. The electric field of radially polarized focal beam in a defocus plan calculated by Debye theory is induced as input source using the total/scatter field approach. We simulated the focusing processes in single dielectric medium and through the interface of two dielectric media, respectively. The distribution of electric field of the focus obtained from the FDTD results coincides with that directly calculated by Debye theory, which proves the facility of FDTD method for simulating the focusing optical field. Additionally, we simulate the focusing of radially polarized beam through dielectric half ball shaped nano-holes with different sizes. The focus shift effect caused by the different sizes of nano-holes provides the mechanism for changing the longitudinal position and the lateral resolution of the focus in subwavelength scale. At last, the surface plasmons excited by the radially polarized focus are shown at the surface of the metallic film and form a smaller focus. The simulation results of this paper will give contribution to the super-resolution focusing for nano-lithography.

In this paper, the diffraction intensity of the Maxwell fish-eye spherical lens is analyzed using the matrix optic theory and the experimental setup. In addition, the diffraction intensity of the homogenous spherical lens is given basing on Kirchhoff's diffraction theory. Comparing the theoretical data and the experimental data of the Maxwell fish-eye spherical lens and the homogenous spherical lens, respectively, there are good agreed with each other. Results indicate the diffractive intensity of the Maxwell fish-eye spherical lens and the homogenous spherical lens is lager than 95% and smaller than 80%, respectively, and the Maxwell fish-eye spherical lens has smaller focusing size than the homogenous spherical lens.

We developed a glasses-free 3D stereoscopic display using an LCD display panel and a special grating film for stereoscopic viewing. The display screen is divided in half in order that left and right regions provide the stereoscopic images for left and right eyes. Because both stereoscopic images are not in the same position, it is difficult for the observer to view the 3D image by the stereoviewing. The grating film can solve this problem because it shifts both left and right images to the same position. Moreover this grating film can give us glassesfree 3D viewing because of its view control effect. As the result, the observer can watch overlapped stereoscopic images for left and right eyes without special glasses such as polarized glasses.

A simple optical path for fabricating photonic crystals is presented. It is convenient to change the number of beams and its angles. Then photonic crystals of different lattices can be gotten. Recording material is home-made water-resisting photopolymer. The fabrication of photonic crystals with holography is simulated by matlab. By changing the number of beams and its angles, triangular, square and circular structures of photonic crystals are obtained. When polarization states of beams are changed, photonic crystals of different refractive index modulation are obtained. Via the simulation, the refractive index modulation of linearly polarized light is the highest. In the experiment, different exposures are set. And the best exposure is 20s, which is less than before. In this paper, photonic crystals using four light beams and five light beams are fabricated. Then, compare simulated results with experimental results and they are in substantial agreement.

The structure combining the microlens and DOE is not sensitive to the incident beam and can control the overall shape profile flexibly. So that the structure called DOE array is designed in this paper in order to shape the unstable laser beam to the four polar uniformity distribution. The paper gives the principle of the DOE array and the design process. The array element determines the profile of the output beam. It is designed using the G-S algorithm and the Adaptive Addition algorithm (A-A). The number of the DOEs is optimized and analyzed. The simulative diffraction efficiencies are 89% and non-uniformities are less than 3% when the incident beams are Gaussian, supper-Gaussian, paraboloid and random distributions. In experiment, diffraction efficiency of 77% and maximum non-uniformity of 5.6% are got on the condition of the different input laser beam. So the effect on the instability of the incident beam could be decreased.

The method of digital holography wavefront reconstruction with adjustable magnification is introduced. Since there is strong zero-order diffraction interference on the reconstruction plane, three different methods are proposed to eliminate zero-order diffraction interference, and compared through experiment. The experimental results demonstrated that the mean subtracted from a hologram is an effective method.

The sampling conditions of calculating the angular spectrum diffraction transform using FFT are deduced in the paper. Combining the Gerchberg-Saxton (GS) algorithm with the angular spectrum theory of diffraction, the design method of binary optical element to realize beam transformation is advanced. And a design example of the diffraction element in marking pattern is also given.

Papers or displays show us an image. The direction to observe these views generally is determined. If you watch the view from opposite side, you perceive an upside down image. In this paper, the authors propose the optical technique for 360 degrees all-around viewing. Using our new technology, you always perceive a correct image even if you see a printed material or an electronic display on the tabletop from opposite side.

The analysis of scattering characteristics of diffractive optics based on Finite-difference time-domain method is presented. And its scattering pattern along the surface is gotten. It shows that the scattering intensity in the discontinuous surface is much higher than the continuous surface. This causes the decrease of diffractive efficiency. Binary optics with multilevel relief can cause more scattering than micro optics with continuous relief, so it is not suitable for being used in the situation where phase varies rapidly.

Taking gratings with periodically varying slit width as two groups of diffraction hinge unit, light radiates on the gratings, each diffraction unit produces diffraction respectively, and then it is equivalent to interference of two beams of coherent light. Using the theory of light diffraction and interference, by means of the diffraction light intensity distribution function of equal slit width, the light intensity distribution law of Fraunhofer diffraction is analyzed for transmission grating of periodically varying slit width. Based on the discussion of general results obtained, the diffraction light intensity distribution and light-shade stripe conditions are obtained for gratings with special slit width and nick width, the diffraction pattern and light intensity distribution curves are plotted through computer simulation.

Waveguide grating couplers with gradually changing periods has good focusing effect to diffraction light; it can provide a compact, efficient coupling mechanism for optical interconnection. In this paper, a polymer waveguide grating couple to vertically couple and focusing for optical interconnection is proposed and designed. In order to estimate the coupling performance of the proposed coupler, the diffraction characteristics of a focusing waveguide grating coupler with gradually changing periods as an in/out-of-plane couple are investigated. The coupling efficiency and the intensities of the diffracted beams as functions of the grating groove depth are analyzed by solving the Helmholtz equation and the method of transfer-matrix. Their corresponding numerical simulation results are given. The grating periodicity fulfilling -1 order diffraction is designed, and excitation direction is calculated. With the optimized structure parameters showing the high coupling performance, the design of a waveguide grating coupling to vertically couple and focusing simultaneous for optical interconnection is obtained.

Highly dense two-dimensional periodic arrays of nano-scaled silicon pillars present the capacity for acting as photonic crystals which can mould, manipulate and guide light. We demonstrate finite element modelling of silicon pillars based photonic crystals and their effective use in applications like waveguides, multiplexers and switches. The optical wave propagation through these structures was thoroughly simulated and analysed, confirming their high efficiency. Later the fabrication of highly periodic two-dimensional arrays of silicon pillars through the process of etching is also explained. High quality of fabricated silicon pillars is displayed in various scanning electron microscope images. The arrays with pillar radius of 50 nm and lattice constant of 400 nm were successfully utilised as optical waveguides with sharp turns. The experimental results are presented showing a good match with the simulation band gap results. Finally we also present the concept of utilising liquid crystals as an anisotropic medium around the silicon nano-pillars to establish tuneable photonic crystals waveguides. The cell geometry for such a hybrid device is suggested in which by application of voltage the dielectric constant of liquid crystals can be controlled and essentially the waveguides can be tuned.

A novel algorithm of multi-image hiding method is presented based on polarization multiplexing digital holography (PMDH). In our single wavelength PMDH scheme, four beams, two p-polarized beams and two s-polarized beams, are formed by two Polarization Beam Splitters (PBS) in the Mach-Zehnder interferometer. Then two different object waves with mutually orthogonal polarization states interfere corresponding reference waves respectively. Therefore two objects can be acquired from the compound holography recorded by CCD with proper incident angle between two reference beams simultaneously. The hologram storing multi-image is then superposed on the discrete-cosine-transform (DCT) domain of the content image, and the extraction process only requires the watermarked image without content image. Simulation results also demonstrate that the embedded multi-image can be successfully extracted under different kinds of attacks.

In this paper, we report a method for color image reconstruction by recording only one single multi-wavelength hologram. In the recording process, three lasers of different wavelengths emitting in the red, green and blue regions are used for illuminating on the object and the object diffraction fields will arrive at the hologram plane simultaneously. Three reference beams with different spatial angles will interfere with the corresponding object diffraction fields on the hologram plane, respectively. Finally, a series of sub-holograms incoherently overlapped on the CCD to be recorded as a multi-wavelength hologram. Angular division multiplexing is employed to reference beams so that the spatial spectra of the multiple recordings will be separated in the Fourier plane. In the reconstruction process, the multi-wavelength hologram will be Fourier transformed into its Fourier plane, where the spatial spectra of different wavelengths are separated and can be easily extracted by employing frequency filtering. The extracted spectra are used to reconstruct the corresponding monochromatic complex amplitudes, which will be synthesized to reconstruct the color image. For singleexposure recording technique, it is convenient for applications on the real-time image processing fields. However, the quality of the reconstructed images is affected by speckle noise. How to improve the quality of the images needs for further research.

An improved algorithm for diffraction calculation is proposed, which is suitable for near-field and far-field diffraction simulation simultaneously. Angular spectrum method (AS) used frequently in diffraction calculation is based on Rayleigh-Sommerfeld integral formula. It is adaptable to a long range of diffracting distance, because there is not approximation with respect to propagation distance in this formula. However, in numerical calculation the sampling problem of transfer function makes it not adapt to near-field and far-field diffraction simulation simultaneously. In this study, this method is improved by limiting the spatial frequency range of diffracting wave. By using the improved method, the problem existed in far-field diffraction simulation with AS is resolved. Simulating examples are presented to validate the proposed method with band-width limit in the paper.

The multiplexed holographic gratings can achieve simultaneously three-dimensional imaging of an object with the Bragg selectivity. The recording conditions of multiplexed holograms for imaging different depths of the object space are investigated experimentally. We find that the cross talk can be ignored when ΔΖ is approximately more than 2ΔΖ_FWHM, and the cross talk is degenerate with the increase of the depth separation. Further we adopt the point-spread function (PSF) of the imaging system to estimate depth resolution of the volume holographic imaging system. Then to avoid image overlap we examine multiplexed holograms recorded with different Δθ. We also calculate Δθ theoretically, and find that the theoretical value is consistent with the experimental result. The optimized holographic gratings are used to image the resolution target which is located at the different longitudinal positions to simulate a 3D object. The results demonstrate that the resolution target located at the two different depths can be reconstructed and clearly imaged on CCD.

A novel subwavelength focusing using an nanohole patterned structure or nano-photon sieves(NPS) is proposed. By employing a nanohole array instead of the ring pattern in conventional Fresnel micro-zone-plate(FMZP) and incorporating a Gaussian modulation function on the density of the nanohole array, it is found that the side lobes of the NPS can be effectively suppressed compared with that of FMZP and both the intensity distribution of focal spot and the side-lobes of focal spot exhibit better symmetric behavior than that of the FMZP. The intensity of electric field at the focal plane can be further improved by introducing a multi-layer system with a dielectric transition layer(i.e. NaF).

We demonstrate a narrow-bandwidth tunable optical filter in the telecommunication wavelength region near 1550 nm using photorefractive grating. Holographic gratings could be written by plane waves of green light using CW 532nm laser as recording source. The filter could be tuned by changing the grating spacing by means of changing the incident angle of the recording beams of grating. Through theoretically consideration, we get a diffractive efficiency up to 80% and a bandwidth less than 0.1nm. Besides, we propose a holographic recording setup.

The transmission characteristics of the electromagnetic waves through the coupled-resonator optical waveguides based on the two-dimensional oval-rod photonic crystals are studied by the finite-difference time-domain method. The simulated results show that the guided mode region can be controlled by partially changing the circular rods with oval rods adjacent to the cavities, and the oval rods' rotating angles are set to be different. When the rotation angle of the oval rods around one cavity is different from the rotation angle of the oval rods around the adjacent cavities, the group velocities of the guided modes can be greatly reduced and high efficiency of light transmission is insured. And the information of different frequencies can be shared and chosen at the same time by the waveguide branch based on the above structures.

A micro-spectrometer which adopts the holographic concave grating as imaging and dispersing element is introduced in the paper. Using ZEMAX soft ware tools, the optimal design of aberration correction of the concave grating which retains the image quality without sacrificing the resolution is coming up with. The portable micro-spectrometer with F/#4 is developed. During 350nm to 800nm wavelength range, the resolution of this kind of micro-spectrometer is better than 0.5nm. In addition, the diffraction efficiency of the concave grating, which is a very important indicator of the spectrometer and confines the detecting ability to the faintest spectrograph, is calculated by means of the rigorous coupled wave theory of the grating. The relationship between the diffraction efficiency of the concave grating and its profile parameters is discussed, too. The results obtained from these researches provide the necessary guidance in fabrication of the micro-spectrometer.

Lengthways and transverse offset of the position of the virtual image relative to the object are analyzed theoretically in different situations of bi-grating imaging, and an experiment on the verification of the offset is carried out. The result shows that the position of the virtual image is just behind the object relative to the positive direction of Z axis, the distance between virtual image and object increases with the increasing of the distance between object and grating G₂; Therefore, the position of virtual image deviates from objects in the X-axis if looking it through grating G₂. Thus the grating G₂ and the virtual image are "located on" the same side of the Z-axis.

The single wavelength off-axis reflection digital holographic microscopy (DHM) can be applied in micron optical tomography measurement through the pre-magnification method. The pre-magnifying surface profile of the object is imaged by the lens placed in front of the object to be measured, and then is recorded by the CCD camera. The Reconstructed image can be got through Fresnel Diffraction calculation, the 3D surface shape information of the object was shown after the phase filtering and unwrapping process to the reconstruction image. The result in this experiment proves that off-axis reflection digital holographic microscopy can be applied to actual measurement of micron object, to achieve the tomography without touching or breaking the object.

Two time-stacked spectral amplitude code (SAC) labels have been demonstrated by simulation to be recognized by filtering their own corresponding unique four wave mixing (FWM) tones in the forwarding nodes which are converted to be an electrical signal to control the routing direction of the packets. In this scheme, the payload does not need to be delayed by a strict time slot and it can not be chopped by the time gating signal so that the useful data is prevented being lost. The forwarding of the whole packet for two nodes and an error-free (bit-error rate< 10^-9) 100 km single-mode fiber (SMF) transmission have been implemented with 0.1-dBm and 0.3-dBm power penalties in the first and second forwarding nodes, respectively, which shows an essential transmission performance.

In this paper, a new method of calculating the diffraction efficiency for diffraction / refraction infrared hybrid system is given. By using this method, an automatic measurement system is designed. This system covers the wavelength range of 1~3 μm, 3~5μm and 8~12μm. We use a blackbody as the energy source, put the lens which is to be measured above a computer controlled turntable in order to gain different results in different filed of view. We also have several relay lenses to cope with long or negative focal length. We use two types of detectors to deal with wavelength range of 1~3μm and 3~12μm .Both the detector and preamplifier are assembled together so we can easily change them for different wavelength ranges. To improve the accuracy of the measurements, a new theory of measuring the main energy is developed to minimize the negative impacts of other diffraction orders and the environment. We use an adjustable slit cooperating with a two-axis stage to scan the focal point and by adjusting the width of the slit we can reduce the energy of other diffraction orders and the environment that may come into our detector. During the experiment process we can manually control the slit and two-axis stage to improve the efficiency and use our computer program to improve the accuracy. The energy modulator and lock-in amplifier also help to improve the accuracy of our system. We designed two standard lenses for the 3~5μm wavelength range. Both of them are made of the same material, have the same focal length of 200mm and their shape is almost the same. The only difference between them is that one of them is pure refraction piece which acts as a reference and the other one has a diffraction surface to achromatic aberration. The result fits our theory well and the possible causes of the differences are discussed. This system has a practical meaning in the quality evaluating of infrared hybrid system.

The physical mechanism of the air impurity in volume holographic photonic crystals was investigated in this paper. The photonic forbidden band with the air impurity was analyzed and calculated by the transfer matrix method. Verifications were carried out using one dimensional holographic photonic crystals made with Dichromated Gelatin (DCG), and the impurity modes were observed.

Because of the inherent structures, most common gratings always produce an unexpected loss of the input signal, which limits the use of gratings in many fields to some extent. Considering that, a design of grating with many periodical micro isosceles prisms is proposed. Based on the scalar diffraction theory, the transmittance is derived from the definition of an optical path when a parallel light passes through a singular prism element. And according to the multi-slit Fraunhofer diffraction, the expression of light intensity distribution for the prism grating on the frequency plane is deduced and analyzed by means of Fourier transform.

Gratings are very important optical diffraction elements in fields of optical communication, optical information processing and optical precise measure, etc. But because of their structures, most common gratings will produce an unexpected loss of the input signal. Considering that, a new design of grating with many periodical micro isosceles prisms is proposed. Each periodical element of this new design looks like a combination of two periodical elements of a blazed grating, and the space frequency of the grating is small, so based on such an equivalent and according to scalar diffraction theory, the detailed expression of diffraction intensity of the prism grating is deduced and analyzed in this paper.

The heavy metal oxide glasses containing bismuth such as bismuth sesquioxide show unique high refractive index. In addition, the bismuth-oxide based glass does not include toxic elements such as Pb, As, Se, Te, and exhibits well chemical, mechanical and thermal stability. Hence, it is used to fabricate high nonlinear fiber for nonlinear optical application. Although the bismuth-oxide based high nonlinear fiber can be fusion-spliced to conventional silica fibers and have above advantages, yet it suffers from large group velocity dispersion because of material chromatic dispersion which restricts its utility. In regard to this, the micro-structure was introduced to adjust the dispersion of bismuth-oxide high nonlinear fiber in the 1550nm wave-band. In this paper, a hexagonal solid-core micro-structure is developed to balance its dispersion and nonlinearity. Our simulation and calculation results show that the bismuth-oxide based photonic crystal fiber has near zero dispersion around 1550nm where the optical parametric amplification suitable wavelength is. Its dispersion slop in the communication wavelength range is also relatively flat. Moreover, both nonlinear coefficient and model filed distribution were simulated, respectively.

Polarization imaging is a powerful tool to observe hidden information from an observed object, for instance, degree of polarization, polarization azimuth and polarization ellipticity. According to the request of the visible light polarization imaging, a metal sub-wavelength polarization gratings array was designed based on FDTD method. And its principle was analyzed by effective medium theory. The effects of metal thickness and duty ratio on the TM and TE polarization transmission efficiency as well as the extinction ratio was analyzed by FDTD method when the grating's period is 200nm and 250nm, and the metal is Al. When the metal sub-wavelength polarization gratings array works in normal incidence, its TM transmission efficiency are more than 45%, and the extinction ratios are more than 3.5×10³ in all visible light spectrum. Numerical results and theoretical analysis show that the designed metal sub-wavelength polarization gratings array is a polarizer with high TM polarization transmission efficiency and high extinction ratios.

The aspheric technology has been largely restricted by testing methods. In particular, the acquisition of the dynamic measurement for different aspheric surface is still a challenge. The reconstruction of the reference wavefront based on spatial light modulator is studied in this paper. Computer-generated hologram is been loaded into the SLM and the standard wavefront is reconstructed. Considering the effect of the SLM grid structure on wavefront accuracy, the theory model of SLM diffraction is analyzed and the elimination methods of SLM structure influence are proposed. Then based on theory analysis, the reconstructed wavefront is demonstrated by using computer simulation. Finally, the corresponding experimental apparatus is built and the wavefront accuracy is analyzed. The experiment results show that the method has achieved worthy measurement precision and has great development potential for optical shape measurement.

In this work, the characteristics of the subwavelength patterning through periodic metal gratings are discussed. By incorporating different structures of metal gratings, the quality improvements in subwavelength pattern generation are observed in terms of pattern resolution, uniformity and visibility. By using Ag and Al metals, a deep subwavelength (~λ/12 and ~λ/9) pattern with sufficient visibility, and high uniformity can be achieved. The physical mechanism of the quality improvements based on surface-plasmon polaritons (SPPs) theory is discussed. Finite-difference time-domain analysis method is used in the simulation.

A new scheme for multiple binary image hiding is proposed. The digital methods of the bit-plane composition and the jigsaw transform are both introduced into the double phase modulated system. By the combination of the digital and the optical methods, the direct superposition of multiple images in most of present techniques is easily avoided. As a result, the proposed scheme is available to hide sixteen binary images without any noises. It implies that a quite satisfactory trade-off between the fidelity and the multiplexing capacity is achieved. According to the results of computer simulations, we also analyze the performances of the proposed scheme including the security, the complexity and the flexibility.

Multiple-image encryption by spatial information prechoosing and cascaded blocks scrambling is proposed. The spatial information of secret multiple-image is pre-chosen in advance to effectively reduce the capacity burden of following encryption system. It is conveniently achieved by selecting or compressing the spatial information of multiple images to meet practical demands. Spatially pre-chosen multiple images are reformed to a new image. Cascaded double random phase encoding system is used to encrypt the new image, and the blocks scrambling is operated at the input of each sub-encoding system. Two main advantages are obtained: 1. Since the spatial information prechoosing enables the whole system to afford much larger information capacity, the effective multiplexing capacity is improved greatly; 2. The combination of blocks scrambling and cascaded random phase encoding not only ensure the much higher system security, but also save the key space and easy the key to save and release compared with the methods by each pixel scrambling. Computer simulations have shown the effectiveness of this method.

The optical add/drop multiplexer (OADM) is an important device to realize an auto optical exchange in optical transport network, and tunable filters are one of its central parts. The acousto-optic tunable filter (AOTF) has not only a large wavelength tuning range (more than 100nm), low optical loss (less than 5dB) and a narrow filter bandwidth (about 1nm), but also dynamic and reconfigurable characteristics. Thus, the acousto-optic tunable filter (AOTF) is one of powerfully several potential candidates. In the paper, the main works are to test and analyze the sidelobes characteristics of TeO₂ AOTF with different bandwidth and its influence on the crosstalk between the neighbor channels. The new structure of OADM based on the AOTF is suggested to lower the influence of signal crosstalk.

This paper researches the phenomenon of bi-grating imaging by the computer simulation. The process that white lights are diffracted by two gratings with different space frequencies is simulated and the imaging characteristics are studied. A bi-grating imaging relationship is given based on the simulation results. It agrees basically with the experiments.

In this paper, a multiuser, asynchronous coherent OCDMA over WDM PON transmission system with DQPSK modulation and balanced detection is proposed and investigated theoretically to combat noise in the OCDMA system. The system is enhanced confidentiality by using DQPSK modulation and balanced detection.

A polarized color filter with good performance is proposed. This device consists of a transparent substrate, a bottom metal grating, a low refractive index dielectric layer, a high refractive index dielectric layer and a top metal grating. The bottom metal grating has a small period which is mainly for polarization, and the top metal grating with a large period is for color-filtering. The parameters that affect the transmission and polarization properties of the device have been simulated and analyzed by utilizing the finite-difference time-domain (FDTD) method. A polarized color filter having broadband peak, high transmission and high extinction ratio is designed. The peak wavelengths and the corresponding transmittances are as follows: 635nm and 78.7% for red, 541nm and 83.2% for green, 452nm and 82.4% for blue. Extinction ratio above 1000:1 has been achieved within the full width at half maximum (FWHM) range for all the three colors. This device is suitable for liquid crystal displays.

A reflection heat source including a radiator as well as an aluminum plate is designed, and the temperature field of the aluminum plate is used as the tested object. The reflection lensless Fourier transform (LFT) digital holography is performed to measure the temperature field distribution. For the comparison, the temperature measurement system within the radiator is used to measure the temperature distributions. The results obtained by these two methods are in good agreement, which demonstrates that the digital holography method is valid for the measurement of the temperature distribution.

In this paper, a general scalar model to analyze the diffraction spectrum of holographic variable line space (VLS) plane grating at oblique incidence is proposed. The analytic expression for the diffraction spectrum of a VLS plane grating at oblique incidence with a parallel and uniform beam was obtained on the basis of Fraunhofer diffraction theory. And the applied scope of the analytic expression is that the grating period is much larger than the incident wavelength. Then some computing examples are given in the condition of single wavelength incident. This oblique incidence model can provide a theoretical reference for the real distribution of diffraction spectrum of holographic VLS plane grating. In future work, the diffraction efficiency and polarization state will be considered.

The imaging technology of digital microscopic image plane holography (DMIPH) is studied in this paper. The point spread function expression and the recording conditions of DMIPH system are derived. The quadratic phase factor which introduced by the microscope objective lens can be eliminated through choosing the proper position of the reference point source when the hologram is recorded by spherical reference waves. By using plane waves and spherical waves as reference waves respectively two image plane holographic recording systems are built. Using a USAF test target as microscopic object, the recorded digital holograms are reconstructed by angular spectrum algorithm. The experimental results show that in the case of spherical reference waves if the distance from the equivalent of lighting point source to CCD plane is equal to the distance between the reference point source and CCD plane the quadratic phase distortion introduced by the microscope objective lens can be removed and that DMIPH is superior to common digital holographic microscopy.

This paper has further studied the implementation methods and recording conditions of digital microscopic image plane holography (DMIPH). Two optical systems of DMIPH were built: one is recording hologram by using plane waves as reference light, the other is recording hologram by spherical reference light. Breast cancer cells and USAF resolution test target is used as tested samples in the experiment. Then the intensity distribution and three-dimensional shape information of the cells are got accurately. The experiment results show that DMIPH avoids the process of finding recording distance by using auto-focusing approach. The recording and reconstruction process of DMIPH is simple. Therefore DMIPH can be applied to the microscopic imaging of cells more effectively.

Two-dimensional phase unwrapping algorithm is the important step and key technology of three-dimensional shape measurement. In order to obtain the appearance characteristics of the object more accurately, a new phase unwrapping algorithm based on unweighted least-squares is presented in this paper, which is an improvement of discrete cosine transform (DCT) phase unwrapping algorithm. The advantage of this method is not only because of the global algorithms, processing the image as a whole, each pixel's value in the image is uniquely determined by solving the Discrete Poisson's equation with Newman boundary conditions which makes the least-squares solution of the wrapped and unwrapped phase difference minimum, but also can reduce the residues effectively. Through computer simulation, this new method and the original DCT algorithm were compared. Theoretical analysis and the results prove the validity of this method .The improved algorithm can eliminate the residues in the wrapped phase pictures more effectively. The phase information of the object can be reconstructed more accurately.

A new method for synthesizing computer-generated holograms of 3D objects has been proposed with reduced number of projections. According to the principles of paraboloid of revolution in 3D Fourier space, spectra information of 3D objects is gathered from projection images. We record a series of real projection images of 3D objects under incoherent white-light illumination by circular scanning method, and synthesize interpolated projection images by motion estimation and compensation between adjacent real projection images, then extract the spectra information of the 3D objects from all projection images in circle form. Because of quantization error, information extraction in two circles form is better than in single circle. Finally hologram is encoded based on computer-generated holography using a conjugate-symmetric extension. Our method significantly reduces the number of required real projections without increasing much of the computing time of the hologram and degrading the reconstructed image. Numerical reconstruction of the hologram shows good results.

In this paper, a method of reduction speckle noise in digital holography is presented. This method can suppress the speckle noise effectively. First, a series of digital holograms are recorded with different titled plane wave illuminations. Then each of the complex amplitude is reconstructed. The speckle noise is suppressed by incoherent superposition of the reconstructed intensity image fields. One of the advantages of this method is that the procedure is very simple and effective. We make computer simulation by applying Fresnel transform algorithm and multiple reconstructed intensity images of a picture with different titled plane wave as illuminating object light. The simulation results show that the more the superposition of reconstructed intensity images, the better the reduction of speckle noise. And it also demonstrates the validation of the present method.

With the recent technological advances, there is an increasing need for testing the microstructure of objects. We show here Digital Holographic Microscopy (DHM) that implements digitally the principle of holography. It is particularly well suited for recording and reconstructing three-dimensional objects. In this paper, we present an off-axis digital holographic configuration and address some basic issues of the off-axis lensless Fourier transform digital holography including the recording conditions and the methods to improve the imaging performance. Following the theoretical analysis, the simple imaging system with the off-axis arrangement is built. Through using the resolution test target as microscopic object, the recorded holograms are reconstructed digitally based on the principle of Fresnel diffraction. The experimental results are consistent with the theoretical analysis. In addition, from the experimental operations and the design of reconstruction procedure we can see that the off-axis lensless Fourier-transform digital holographic setup is simple and suitable for real-time applications in microscopy.

The volume phase holographic (VPH) transmission grating recorded in dichromate gelatin (DCG) with a specific spectral coverage from 420 nm to 760 nm is designed for a novel prism-grating-prism imaging spectrometer. Based on the Rigorous Coupled-Wave Analysis, its performances are predicted and analyzed. The grating is manufactured and its properties are measured experimentally. The diffraction efficiency over the spectral range, the bandwidth, and the angular selectivity of the grating is measured, analyzed and compared with that of the theoretical ones. The results show that by adjusting and controlling the preparation conditions of DCG plates, the exposure time and the post-processing technique of the grating, the VPH transmission grating with high diffraction efficiency approximate to the design requirement can be obtained. The measured peak diffraction efficiency reaches nearly 85% at central wavelength of 590 nm while the average diffraction efficiency is larger than 75% over the required spectral range from 420 nm to 760 nm.

A novel passive optical network (PON) over optical code division multiple access (OCDMA) uplink based on the differential quadrature reference phase shift keying (DQPSK)/ on-off Keying (OOK) orthogonal re-modulation and time domain phase coherent OCDMA en/decoder scheme has been proposed. The bit error rate and receiver sensitivity of the system have been investigated, and the security performance and MAI (Multi Access Interference) property of the OCDMA uplink data have also been investigated. The results show that the proposed PON system is more cost-effective with less power penalty, and the capacity and security of upstream data can be greatly improved .

A fused-silica polarization grating at a wavelength of 1053 nm was designed. To achieve a high extinction ratio and efficiency, the grating profile was optimized by using rigorous coupled-wave analysis. The results showed: when the grating period, the duty cycle and the groove depth of polarization grating were at 650nm, 0.39 and 1340nm respectively, the extinction ratio could reach the maximum 34700; the efficiencies of the TE-polarized wave in the -1st order and the TM-polarized wave in the 0th order were 92.2% and 99.5% respectively. We also analyzed the effects of the deviations of the period and depth from optimized parameters on the extinction ratio and efficiency. The holographic lithography and the ion beam etching will be applied to fabricate a prototype polarization grating in late 2010.

A method of encoding eight objects simultaneously in a detour computer generated hologram(CGH) is proposed. In the method, we divide eight objects into two groups and multiple objects are encoded through synthesized spectrum. The simulation demonstrated the effectiveness of the method. In the reconstruction two groups of objects were reconstructed around the same diffraction order along x, y directions, respectively. The result showed that the method can improve the information capacity in a CGH efficiently.

The focusing of the focused Gaussian beam by a spherical aberration micro-lens is investigated by Monte Carlo simulation. This method takes into the images affected by the primary even higher orders aberration with no paraxial approximation. The effect of the negative spherical aberration on the radial intensity distribution, spot size and focal shift are discussed. The simulation results show that when the Gaussian beams are focused by a lens with spherical aberration, the radial intensities distributions in the geometrical and best focal plane had two maxima, and the maxima point are not located in the optical axis. And with the Fresnel number increasing, the simulation focal shift curve approach the curves calculated by the formula for an aberration-free lens.

In this paper we propose the new method of nondestructive checking, based on application of the fractal masks photographed through the objects under study. Coherent optical image processing of the fractal masks allow to receive the separate information about components of the refractive index gradient and phase discontinuities. The power of high spatial frequencies of the fractal mask spectrum is three times greater in comparison with spectrum of regular mask. The analysis of results of the inverse Fourier transform of the distorted spectrum of regular and fractal masks shows that the fractal mask is more sensitive and allows to obtain the value of distortion of the initial object more precisely.

The article describes the results of analytical and computer simulation of Fresnel diffraction from phase-type zone plates with fractal structure. The focusing properties of phase-type fractal zone plates (FZP) with different fractal dimension and phase depth are studied. It is shown that the axial irradiance exhibits selfsimilarity properties with additional focal points. It is demonstrated that FZPs reduce chromatic aberrations under white-light illumination. In addition, for the first time the FZPs with variable phase depth are presented. It is shown that axial irradiance and position of principal focus depend on these parameters.

This paper propose a complete design and implementation of a controlling and data acquisition scheme for the demodulation of Quasi-Distributed Fiber Bragg Grating (FBG) sensor system by combining the technology of USB 2.0 and FPGA with precise system adjustment strategies, aiming to meet the requirement of acquiring large amount of data in real time for multiplexing a number of sensors, while maintaining stable control and accurate monitoring over all sensors on a small-sized embedded module. A Xilinx Spartan-3 FPGA and several DACs, including LTC1450 and LTC1597 are used to control a F-P filter as a wavelength selection element for demodulation, as well as realizing adjustment and stability of the whole sensing system while a high speed data path is conducted by the same FPGA and a Cypress USB controller. A newly designed method for rotational data transfer is applied to complete signal compensating and system adjustment. A quasi-distributed FBG sensing system with precise control and stable coordination can be achieved while the sensing data is easily obtained without losing details.

Extreme Ultraviolet Lithography (EUVL) is the leading candidate for Next-Generation Lithography (NGL) in the sub-45 nm regime. One of the critical technical problems to be solved before the commercialization of EUVL is the control of image placement errors during EUVL mask blank fabrication. This paper focuses on the characterization of image placement errors induced by the thin film stresses during EUVL mask blank fabrication. Firstly, the causes and classifications of the stresses in the thin films were discussed. Then an analytical analysis was developed to reveal the effects of the thin film stresses on the distortions of the EUVL mask. Lastly, finite element (FE) models were established to simulate each process step in EUVL mask blank fabrication. The out-of-plane distortions (OPD) and inplane distortions (IPD) were tracked for each process step. The numerical results are compared with the analytical results to validate the FE models. Comparison indicated that numerical results and theoretical results agree very well with each other. The research in this paper provides a solid support for EUVL mask blank fabrication, theoretically and numerically. Further mounting and chucking procedures can keep image placement errors within the allotted error budget as well as provide the necessary flatness.

According to the latest ITRS Roadmap, extreme ultraviolet lithography (EUVL) is expected to be one of the principal carriers for the IC production at sub-45 nm technology nodes. One of the most challenging tasks to fulfill EUVL is the fabrication of the EUVL mask in which the most important issue is the control of image placement errors. In this paper, the EUVL mask fabrication process was analyzed and image placement errors due to the fabrication process were investigated and predicted. A theoretical analysis was conducted to analytically benchmark the EUVL mask fabrication process. A line-and-space pattern (with pattern coverage of 50%) was employed in the theoretical analysis as an example. The theoretical deduction revealed that this 50% coverage pattern produces the same global response as a uniformly stressed thin film with half of the stress-thickness product of the patterned lines. Finite element (FE) models were established to simulate the EUVL mask fabrication process. In FE simulations, a new equivalent modeling technique was developed to predict the global distortions of the mask and the local distortions of the pattern features. Results indicate that for the EUVL mask with this line-and-space pattern (50% pattern coverage), the maximum image placement error is only about 10 nm, which is largely due to the application of a flat electrostatic chuck in both e-beam mounting and exposure chucking. Nonuniformities of either the mask or the electrostatic chuck will add to the final image placement errors of the EUVL mask.