This PDF file contains the front matter associated with SPIE Proceedings Volume 7935, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

Specific spatially-anisotropic interactions are identified that enhance noncentrosymmetric order required for electro-optic activity. Enhancement of electric-field-poling-induced noncentrosymmetric order by these specific interactions is shown to result from a reduction of lattice dimensionality from three to two dimensions. New analytical techniques for measurement of centrosymmetric and noncentrosymmetric order and lattice dimensionality are introduced. Measurement of order parameters is correlated with viscoelastic data to gain further insight into the influence of specific interactions on poling efficiency and thus material electro-optic activity. The integration of organic electro-optic materials into silicon photonic, plasmonic, and metamaterial devices is also discussed. These device structures can affect the "effective" optical nonlinearity of organic materials but care must be exercised to control optical loss.

In order to combine both advantages of organic and inorganic materials and to solve the problem of mobility mismatch between hole transport layer (e.g. NPB) and electron transport layer (e.g. AlQ) of organic light emitting diodes, a mobility-tunable HTL of silicon-rich silicon oxide (Si_1+xO₂) is proposed. By changing the degree of excess silicon x, the mobility of Si_1+xO₂ can be controlled into a suitable range of ~10^-5 cm²·V^-1·s^-1 which matches well with that of AlQ. The organic light emitting devices fabricated on silicon substrates have a lower operating voltage of 6.0 V and a higher maximum power efficiency of 0.33 lm/W.

Considering the practical applications of liquid-crystal microlasers, such as laser displays and opto-communication devices, broadband tunablity and continuous wave (cw) operation are strongly desired. Especially for the later one, nobody has succeeded yet. For the cw operation, two problems must be solved: (1) Development of new dyes which are stable against heat and light; (2) Development of novel cavities with high Q which makes the lasing threshold lower. Here in this paper, we will introduce our recent researches mainly aiming at reduction of the lasing threshold in liquid crystal microlasers; (1) single-output window devices; (2) multilayered devices; (3) use of a polymer dye improving order parameter; (4) a new laser dye specially designed for dye-doped CLC lasers.

Based on the distributed structure of the dye-protein complexes in a photosynthetic membrane, tandem structure with two dye-doped polymer layers was fabricated using the nanoimprint lithography. The energy transfer behavior of different tandem patterns were studied using fluorescence microscope. As a result, duty ration of 1:1 has shown the even fluorescence patterns from the acceptor region, whereas the patterns with higher duty ratios had shown only partial fluorescence from the donor-acceptor interface.

In this work, we had studied the Amplified Spontaneous Emission( ASE) properties of polymer BEHP-co-MEH-PPV in THF, under pulsed laser excitation. In our earlier communication, we had shown that MEH-PPV alone could produce ASE under pulsed Nd: YAG laser excitation only in its excimeric state. A follow up study reported here, on conjugated polymer shows that in BEHP-co-MEH-PPV, the BEH-PPPV component is capable of forcing MEH-PPV to produce ASE at 560nm, which appears to arise out of the monomeric state of MEH-PPV. It is important to note that BEHP-PPV as a part of the compound could get excited by pump laser pulse, and transfer its excitation energy internally to MEH-PV helping MEH-PPV to produce ASE in non excimeric state. Also we had investigated the energy-transfer process externally from the donor coumarin485 (C485) to acceptor MEH-PPV By this processes also MEH- PPV could be forced to produce ASE from the monomeric state

Conjugate Polymers are novel optoelectronic materials with wide range of applications. In this paper, we present the results of fluorescence and laser excited amplified emission spectra of MEH-PPV polymer, which has some surprising laser properties. (MEH -PPV) is a complex macro molecule. When this is dissolved in liquids like, tetra hydro furan (THF), it is very fluorescent, with quantum yield comparable to conventional laser dyes. This polymer has absorption peak around 490nm and emission peak at 560nm for a low concentration (1 micro molar). However for higher concentration (10 micro molar) it has a new band at 600nm, in emission only without any new band in absorption. This is a strong indication of excimer formation. When this particular solution is pumped by a 3rd harmonic of Nd-YAG laser (355nm and 11 ns), the polymer underwent strong excitation and population inversion and amplified spontaneous emission (ASE) at 600 nm only. For lower concentration, we could get fluorescence only with a peak at 560 nm. That is, this particular polymer produces ASE and hence laser only from the excimeric state. It is important note that most of the liquid laser dyes do not produce laser from the excimeric state; other solutions which are easily forming excimeric state do not laze. This appears to be the only liquid excimeric state laser. Another important feature of the solution it is at least 10 times more stable than the conventional laser dyes.

DNA biopolymer has emerging as a promising material in photonic applications. In this paper, we present the preparation and characterization of a series of DNA-surfactant complexes based on aromatic surfactants, including vinylbenzyltrimethylammonium chloride, benzyltrimethylammonium chloride, and phenyltrimethylammonium chloride. Fourier-transform infrared spectroscopy (FTIR) and UV-VIS spectroscopy were used to characterize the presence of specific chemical groups in the materials. These synthesized DNA complexes show high transparency from 400nm to 1100nm. These materials can be spin casted into thin films from nm to um and the morphology was examined by SEM and AFM. Thermal property was characterized by thermogravimetric analysis. Conductivity was examined to investigate the effect of aromatic surfactants on the electrical properties of DNA complexes. In addition, the photoluminescence and lasing properties for DNA-aromatic surfactants with rhodamine dyes were investigated to study the amplified spontaneous emission where the ASE emission wavelength, lasing threshold, and gain were presented and discussed. The results were compared with DNA complex with single chain aliphatic surfactant complex (DNA-cetyltrimethylammoniumchloride).

We present optical, photoluminescent (PL), and photoconductive properties of functionalized anthradithiophene (ADT) derivatives and their composites. Solution-deposited ADT films exhibit charge carrier mobilities of over 1.5 cm²/(Vs), high PL quantum yields, and high photoconductivity. We show that molecular arrangement and intermolecular interactions significantly contribute to (opto)electronic properties of guest-host thin films of these pi-stacked materials. Specifically, the formation of aggregates plays an important role in establishing efficient conduction pathways in ADT derivatives dispersed in a host matrix. In addition, the extent and nature of aggregation and the resulting changes in PL and photoconductive behavior can be effectively manipulated through different film fabrications techniques. Furthermore, energy transfer and exciplex formation has been shown to occur between two different ADT derivatives, which also alters the photoconductive response of the systems. We explore the dependence of the photoconductive response of such guest-host systems on excitation wavelength.

Improving molecular packing of semiconductor materials in the vicinity of an insulating layer is of primary interest for efficient charge transport in an organic thin-film transistor. Self-assembled monolayers (SAMs) are often employed for this purpose. In other cases, a thin alignment layer is placed on a gate insulator in an attempt to order organic molecules along a specific direction. We fabricated bottom-gate, top-contact pentacene transistors with an underlying photo-alignment layer as follows. Azobenzene-polyamic acid was spin-coated on SiO₂ and was irradiating with linearly polarized ultraviolet light at various energy densities. The material was converted to polyimide by heating and a thin pentacene layer was evaporated on it. Finally, source and drain electrodes were formed by sputtering gold through a shadow mask. The transistors fabricated with the polarization perpendicular to the current direction in the channel showed higher field-effect mobility and the maximum value was 1.0cm²/Vs. This is close to the value reported for the conventional pentacene transistors having SAMs. The mobility decreased as the irradiation energy density increased. Hence, we attribute the anisotropy introduced by the photo-alignment layer to degradation in charge transport in the specific direction.

Japan Science and Technology Agency (JST) have launched a new program called strategic promotion of innovative research and development ( S-Innovation ). Projects chosen for the S-Innovation program are selected from among the research output of JST's strategic and basic research programs, such as CREST, ERATO, Sakigake and PREST, which aim to create innovative new technologies, lead to the advancement of science and technology and the emergence of new industries. S-Innovation covers R&D themes from the aforementioned programs and is based on the seamless, long-term pursuit of R&D toward the practical application of novel technologies. It is envisaged that the innovation resulting from such technologies will form the foundations of future industries. Currently the program consists of four projects in which photonics polymers are included. The photonic polymer research consists of five topics such as development of fast organic photorefractive polymers for advanced optical communication technology, development of new device technology based on nano-ordered structures of polymers, development of three-dimensional vector wave memory, optical interconnect device technology using high performance photonic polymers and development of quantum photonic technologies with polymer optical nano-fibers. Each topic is funded approximately $1.0 M/year for ten years. The objectives and unique features of S-innovation and the highlights of each topic are described.

Highly ordered iron incorporated mesoporous silica (Fe-SBA15) was prepared and used as a template for catalytic polymerization of functional molecules. The mesoporous catalysts were used as an oxidative nano-reactor in heterogeneous catalytic reactions to afford highly fluorescent poly(methylene anthracene)s (PMAn) when anthracene was used as a monomer. The structure of the mesoporous Fe-SBA15 was 2D channel with large surface area of 710 m²/g and pore size of 9.2 nm. The fluorescent polymer was synthesized with high yield of 90 % in short reaction time. The synthesized polymer PMAn showed good emission properties with high excimer emission, which was highly affected by the pore size of the reactor. This indicated that the optical properties of fluorescent polymers synthesized from this method could be controlled by the pore size of the mesoporous templates.

Because PDMS is viscous, it's impossible to form thin films of PDMS using spin coating without dilute it with solvents. We examine the optimal solvents and spin parameters for spin-coating the PDMS elastomer on glass substrates. Chloroform, Benzene, and Toluene have been attempted to study the influences of solvent on forming thin films of high uniformity. The experiments conclude: the solvent with lower evaporation rate produces more uniform films. No strong relationship between spin speeds and film uniformity has been observed when spin speed is high. However, the film uniformity begins to decline when lower spin speed is used. In addition, we find that the refractive index of the thin film can be modified by curing temperature.

Oleic acid capped lead sulfide (PbSe) cubes, spheres, rods and star-shaped nanocrystals with sizes ranging from 5 to 20 nm were synthesized, then subjected to a post-synthesis washing in a 1:1 ethanol/hexane solution. The relationship of third order nonlinear optical properties to nanocrystal surface chemistry as affected by this washing was analyzed using nanosecond 532 nm Z-scan. The results indicated a significant change in optical properties emerged only after the nanocrystals, regardless of shape, were washed in the ethanol/hexane mixture. The "as grown" nanocrystals displayed high emission efficiency with no nonlinear absorption, which converted to a highly-absorbing and strongly scattering media with quenching of optical emission following washing. Transmission electron microscopy showed that neither the size nor shape of the nanocrystals was changed by washing, indicating that all differences were related to changes in surface chemistry. Finally, the Z-scan of washed nanocrystals displayed a strong correlation between nonlinear scattering and nonlinear transmittance which was also not dependent upon shape. It is postulated that the washing allowed formation of deep trap states that permitted nonlinear optical absorption.

We review our work on several strategies to elaborate multifunctional nanoparticules for two-photon imaging or/and photodynamic therapy. Our first strategy is based on the incorporation of two-photon hydrophobic fluorophors in bio-compatible pluronic micelles using the mini-emulsion technique. Our second strategy is based on fluorescent organic nanocrystal grown in silicate spheres. These core-shell hybrid nanoparticles are obtained by a spray-drying process from sol-gel solutions. Our third strategy consists in the encapsulation of hydrophilic molecules in the water core of gold nanospheres. They are obtained by a stabilized emulsion in biphasic liquid-liquid medium without surfactant.

We propose new strategies to increase and control molecular second-order nonlinearities, byusing photoswitching processes or plasmonic resonance. First, we report on reversible switching of nonlinear optical (NLO) properties, based on the use of dipolar or octupolar metal complexes containing photochromic ligands like dithienylethene (DTE) derivatives. DTE undergo a reversible interconversion between a non-conjugated open form and a π-conjugated closed form. A strong relative change of the quadratic molecular nonlinearity upon visible light exposure (more than one order of magnitude) is evidenced by second harmonic generation experiments. This process is fully reversible. On another hand, we explore the quadratic NLO properties of highly NLO dyes (stilbazolium derivatives) grafted onto the surface of gold nanoparticles (NP). In spite of the fact that the plasmon resonance wavelength of gold NPs lies far from that of the second harmonic signal at 820 nm, a significant increase of the nonlinear response of this dye (when linked to a gold nanoparticle) due to surface Plasmon resonance with gold NPs is shown by Harmonic Light Scattering at 1.64 μm. The nature of the linker has a significant influence of hyperpolarizability values, and a similar, but weaker enhancement effect, is also reported in the case of dye/NP mixtures.

We report on the magnetic behavior of pristine, substituted regioregular poly(thiophene)s. SQUID magnetometry reveals ferromagnetic order below 20K in regioregular (RR) poly(3-dodecyl)thiophene (P3DT), while the regiorandom (RRa) counterpart is barely magnetic. The magnetic behavior and strength observed by SQUID magnetometry appears to be governed by the supramolecular structure. Formation of nanodoughnut structures within the relatively short chain RRP3DT further indicates strong role of supramolecular structures towards ferromagnetic ordering.

Second Harmonic Generation was used to study the optical properties of molecular films formed at the air-water interface. The technique was first applied to a two-dimensional film of 4-(4-dihexadecylaminostyryl)-N-methylpyridinium iodide (DiA) formed at the air-water interface in a Langmuir trough. The SHG intensity was measured as a function of the incident fundamental and outgoing harmonic wave polarization angles at different states of the monolayer compression. The film revealed chirality arising from the formation of molecular aggregates and it was demonstrated that this chirality property arose from the coupling of the electric and magnetic fields at the fundamental frequency. In a second stage, we applied the SHG technique to follow the emergence of chirality during the compression of a molecular film of the amphiphilic compound 5-(octadecyloxy)-2-(2-thiazolylazo) phenol (TARC18). A similar behavior was observed and it was shown that the same origin was responsible for the appearance of chirality. Polarization resolved intensity measurements demonstrated that the magnetic dipole contribution was the dominant one.

A versatile optically-gated optical switch using an organic-dye is suitable for light-path switching in an optical communication for various wavelengths of a signal-light. An organic dye for absorbing a gating-light combined with a high-boiling solvent for forming a thermal-lens is properly selected choosing a wavelength of both a gating- and a signal-light. The incidence gating-light passed through a short focal-length lens is absorbed around the focal point and form high-temperature region in the high-boiling solvent, which refract a simultaneously incidence signal-light by a thermal-lens effect. Mechanism of forming a thermal-lens and refracting the signal-light is discussed.

We report an enhanced laser induced polarization switching and holography in a novel photo-reconfigurable material system that contains polymer backbone impregnated by a soft liquid crystal material. The backbone of polymer chains is reconfigurable and the surrounding movable liquid crystal molecules are reoriented collectively anchoring toward the reconfigured polymer chains, resulting in remarkable enhancement of anisotropic refractive index modulation suitable for updatable holographic recording. The dynamic polymer-liquid crystal network strengthening concept enables significant enhancement of holographic performance with controllable updatability.

The future of optical data storage and the search for next generation high-density technologies have become a topic of lively debate. Three dimensional (3D) optical data storage, a relatively new technique which enables hundreds-layer data recording in a hard memory, seems a viable candidate for this role. In this work, we report on 3D optical data storage in photochromic compounds. The recording medium used in the experiments was a photochromic diarylethenes derivative embedded in different host polymers. Multi-photon processes capability of triggering photochemical reactions and physical changes with micrometer-sized resolution in three dimensions offers a well-suited means to achieve volumetric storage densities. A commercial microscope coupled to pulsed NIR and CW lasers have been used to write, read and erase data in our prototype memories. Information was recorded within the volume of the media via a multi-photon process achieving high localized photoconversion and the fluorescence emission from the photoconverted molecules when excited by a 405 nm laser diode was the readout signal. It is also shown that data recorded in such a medium can be selectively erased by irradiating with 514 nm CW laser light giving the chance to write new data in the formerly used memory space. These storage media, thus, have good potentials to achieve volumetric storage of data although they certainly deserve further optimization work to achieve high number of superposed layers and to assure durability of the written data under readout conditions.

The blue shift of viewing angle in the top-emitting organic light-emitting devices is discussed in this study. For the single-mode cavity, the device of anode metal/ m-MTDATA (40 nm)/ α-NPD (10 nm)/ Alq₃ (47.6 nm)/ LiF (1 nm)/ Ag (20 nm) with the metal phase difference of 1.30 π has the minimum blue shift of viewing angle. For the double-mode cavity, the recombination area must be away from the cathode for the device with better performance. However, the double-mode cavity with only one recombination area still has worse FWHM and gets more serious the blue shift of viewing angle than the single-mode cavity. Therefore, the double-mode cavity with a recombination area at each antinode is performed, and the results prove that the blue shift of viewing angle and the FWHM are improved. Finally, we replace the emission layer with Alq₃:DCM (0.01%) and adjust the main peak wavelength in the double-mode cavity by adjusting the thicknesses of the cavity. The results show that the FWHM and the blue shift of viewing angle obtain further improvement for the double-mode cavity with a recombination area at each antinode.

The fluorescent poly(1,3,4-oxadiazole)s (POD) and polypyrene (PPy) were examined for electro-optic device. The fluorescence switching device prepared using poly(1,3,4-oxadiazole)s showed molecular structure-dependent switching properties depending on the para- or meta-linkage. Thin films of POD and PPy were prepared by solution process to give highly fluorescent film, of which emission intensity was switched on and off upon application of step potentials. Using a photochemical reaction, the thin films of POD and PPy were directly patterned to give a fluorescent pattern. An all solid state device containing the patterned films of POD and PPy was prepared using a solid polymer electrolyte layer. The device showed reversible fluorescence switching in response to external voltage applications. Patterning of the switching device in different dimension and scale will be demonstrated.

We have investigated the nonlinear optical properties, optical limiting thresholds, and figures of merits for five different phthalocyanine thin films, achieved through doping in PMMA, using the Z-scan technique at 800 nm with 2 ps laser pulses. From the open-aperture Z-scan data we established that these molecules exhibit strong two photon absorption (2PA) with the nonlinear coefficients in the range of 15-200 cm/GW. We have also estimated the sign and magnitude of real part of third order nonlinearity through the closed aperture scans. Preliminary femtosecond pump-probe data suggests that the lifetimes of excited states are in the sub-100 ps regime for all the molecules in film form. Our studies provide tangible evidence that these phthalocyanines are potential candidates for multi-photon imaging and optical limiting applications.

Effect of electroactive ferrocene on the optical and electrochemical properties of polythiophenes were examined. Thus the ferrocene unit were introduced into polythiophenes by Grignard metathesis (GRIM) method to produce ferrocene substituted polythiophenes (PThFc). These polymers were characterized by GPC, NMR, UV-Vis absorption spectrum, and cyclic voltammogram (CV). The PThFc showed lower redox potential and reversible electrochemical redox state due to the ferrocenyl functional group, as determined by the CV. The absorption maxima of PThFc was 556 nm in the film state with a broad absorption band covering from 350 nm to 650 nm. Fluorescence quenching efficiency of PL for the PThFc containing films was determined as > 90%. The short-circuit current densities (J_sc) for the cell containing PThFc was highly dependent on the thermal annealing process, indicating that the photovoltaic properties could be optimized by the control of polymer structure. (PThFc).