This PDF file contains the front matter associated with SPIE Proceedings Volume 9486 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Recent advances in miniaturization and analyte-sensitive fluorescent indicators make optical fiber biosensors promising alternatives to microelectrodes. Optical sensing offers several advantages over electrochemical methods including increased stability and better spatial control to monitor physiological processes at cellular resolutions. The distal end of an optical fiber can be functionalized with different fluorophore/polymer combinations through mechanical, dip-coating or photopolymerization techniques. Unlike mechanical and dip-coating schemes, photopolymerization can spatially confine the sensing layer in the vicinity of light in a more reproducible and controllable manner. The objective of this study was to fabricate microscale fluorescence lifetime based optrodes using UV-induced photopolymerization. Six commercially available acrylate based monomers were investigated for stable entrapment of the oxygen sensitive porphyrin dye (PtTFPP) dye via photopolymerization at the end of optical fibers. Of these, the acrylate-functionalized alkoxysilane monomer, 3-methacryloxypropyl-trimethoxysilane (tradename Dynasylan MEMO) showed maximal response to changes in oxygen concentration. Dye-doped polymer microtips were grown at the ends 50 μm optical fibers and sensitivity and response time were optimized by varying both the concentration of doped dye and the excitation power used for polymerization. The resulting sensors showed linear response within the physiologically relevant range of oxygen concentrations and fast response times. While applied here to oxygen sensing, the photopolymer formulation and process parameters described are compatible with a wide range of available organic dyes and can be used to pattern arrays of spots, needles or more complex shapes at high spatial resolution.

Surface-enhanced Raman scattering (SERS) provides a non-destructive sensing method with high sensitivity and multiplex detection capability since SERS takes advantage of high enhancement from surface plasmon resonance and unique “fingerprint” spectral signature using Raman spectroscopy. Our group has developed a unique plasmonics-active nanoparticle, gold nanostars, with tunable plasmonics in near-infrared (NIR) “tissue optical window” without using toxic surfactant. We present their applications for chemical and biological sensing with SERS method as well as theoretical studies to investigate and confirm experimentally measured SERS results.

Fundamental limitations of resistance thermometry, as well as the desire to reduce sensor ownership cost has led to considerable interest in the development of photonic temperature sensors as an alternative to resistance thermometers. These innovative temperature sensors have the potential to leverage advances in frequency metrology to provide cost effective measurement solutions. Here we present the results of our efforst in developing novel photonic temperature sensors. Our preliminary results indicate that using photonic devices such as the ring resonators, photonic crystal cavities and Bragg reflectors we can achieve measurement capabilities that are on-par or better than the state of the art in resistance thermometry.

Raman spectroscopy performed using optical fibers, with excitation at 1064 nm and a dispersive detection scheme, was utilized to analyze a selection of unifloral honeys produced in the Italian region of Calabria. The honey samples had three different botanical origins: chestnut, citrus, and acacia, respectively. A multivariate processing of the spectroscopic data enabled us to distinguish their botanical origin, and to build predictive models for quantifying their main sugars. This experiment indicates the excellent potentials of Raman spectroscopy as an analytical tool for the nondestructive and rapid assessment of food-quality indicators.

From anthropogenic sources to natural oceanic emissions, the concentration of methane in the atmosphere has more than doubled in the last 200 years. Since methane represents a global warming potential 23 times an equivalent mass of carbon dioxide, monitoring this species is of great interest. In terms of anthropogenic emissions, landfills represent a significant source of atmospheric methane. We have developed an in-house algorithm for extracting methane concentrations directly from FTIR spectra for gas samples from a local landfill. In this work, we will describe the method and present some preliminary measurements.

We introduce a novel approach to continuous in-situ pathlength calibration of an integrating sphere based gas cell. Using two light sources and two detectors, a four beam ratiometric scheme is constructed, which compensates for component variation and sample chamber contamination. By applying the scheme to both on and off gas line measurements, changes in pathlength due to cell wall contamination can be identified and corrected. In this way the gas absorption coefficient can be determined continuously without needing to recalibrate the sphere. Results are presented for detection of methane at 1651nm. This method has the potential for extension to other gases such as CO₂, CO, H₂S, NO_x.

We report on the measurement of the NO₂ concentration in ambient air using a highly sensitive trace gas detector based on a simplified design that uses a multi-mode diode laser and cavity enhanced multiple line integrated absorption spectroscopy. The broad frequency range of the laser covers a large number of absorption lines of NO₂ and excites a large number of cavity modes. The off-axis cavity arrangement reduces the detector’s susceptibility to vibration. The detector was calibrated using known concentrations of NO₂ in zero air and used to measure the concentration of NO₂ in ambient air in our laboratory. A sensitivity of 75 ppt was achieved.

Fugitive gas emissions from agricultural or industrial plants and gas pipelines are an important environmental concern as they can contribute to the global increase of greenhouse gas concentration. Moreover, they are also a security and safety concern because of possible risk of fire/explosion or toxicity. This study presents gas concentration measurements using a quantum cascade laser open path system (QCLOPS). The system retrieves the path-averaged concentration of N₂O by collecting the backscattered light from a scattering target. The gas concentration measurements have a high temporal resolution (68 ms) and are achieved at sufficient range (up to 40 m, ~ 130 feet) with a detection limit of 0.4 ppm for N2O. Given these characteristics, this system is promising for mobile/multidirectional remote detection and evaluation of gas leaks.

Rapid expansion of the oil and gas industry in Alberta, including the oil sands, has challenged the Alberta Government to keep pace in its efforts to monitor and mitigate the environmental impacts of development. The limitations of current monitoring systems has pushed the provincial government to seek out advanced sensing technologies such as satellite imagery and laser based sensors. The Space Dynamics Laboratory (SDL) of Utah State University, in cooperation with Alberta Environmental Monitoring, Evaluation and Reporting Agency (AEMERA), has developed North America’s first mobile differential absorption lidar (DIAL) system designed specifically for emissions measurement. This instrument is housed inside a 36’ trailer which allows for mobility to travel across Alberta to characterize source emissions and to locate fugitive leaks. DIAL is capable of measuring concentrations for carbon dioxide (CO₂) and methane (CH₄) at ranges of up to 3 km with a spatial resolution of 10 meters. DIAL can map both CO₂ and CH₄, as well as particulate matter (PM) in a linear fashion; by scanning the laser beam in both azimuth and elevation DIAL can create images of emissions in two dimensions. DIAL imagery may be used to understand and control production practices, characterize source emissions, determine emission factors, locate fugitive leaks, assess plume dispersion, and confirm air dispersion modeling. A system overview of the DIAL instrument and some representative results will be discussed.

Mid-infrared (MIR) standoff photoacoustic (PA) sensing of explosive chemicals and nerve gas stimulants at calibrated concentration have been demonstrated in door. When they are operated out door, array beam forming technique has to be employed to reject ambient noise and enhance signal. Lock-in amplifier usually needs to be used to achieve weak signal detection in a noisy environment. If we can combine these two techniques we will be able to reject both spatial and temporal noise and achieve a great signal to noise ratio (SNR) performance. From the best of our knowledge no literature has described how to combine these two techniques. In this work we demonstrated combined array and lock in amplifier operation in outdoor environment. A simplified system includes a signal generator, a speaker source, a lock in amplifier, 4 spy-phones with 4 parabolic reflectors to collect the acoustic signal, a National-Instrument NI6259 data acquisition system with both A to D (ADC) and D to A converters (DAC), and a PC. To combine these two techniques, each of the array collected signals was digitized by the ADC. Their path delays were adjusted in the computer to synchronize the phase. By using a PC controlled ADC the processing time is very long (~1s). To synchronize them without using costly high-speed customer made hardware, we delayed the reference signal by send it through the same ADC- PCDAC path as the array signals. By doing so, a good lock-in operation with stable phase was obtained.

In this paper we present a laser spectroscopy system designed for application in standoff chemical detection. The system is based on a dispersion sensing approach which provides high immunity to amplitude noise and optical power fluctuations. It is well suited for industrial applications (e.g. leak detection) as well as for environmental monitoring (e.g. measuring emissions from distributed sources like wetlands or water reservoirs using single instrument that covers large area with path-integrated detection). A detailed system configuration is presented. Feasibility of standoff gas detection using laser dispersion spectrometer with scattering optical targets is demonstrated.

For three decades or so, microfluidics continued to receive attention. This increasing interest is primarily driven by applications. Example applications range from sensors and actuators, to Micro Electro Mechanical Systems, biotechnology and chemistry. In our laboratory, we have been developing microfluidics primarily for spectrochemical applications, for example, for fabrication of postage stamp size microplasma devices and for sample preparation and processing. The main focus of this paper is to describe fabrication technology developed in our laboratories for fabrication of microfluidics on (relatively expensive) crystalline Silicon wafers and on inexpensive glass chips.

Light scattering patterns from non-spherical particles and aggregates exhibit complex structure that is only revealed when observing in two angular dimensions. However, due to the varied shape and packing of such aerosols, the rich structure in the two-dimensional angular optical scattering (TAOS) pattern varies from particle to particle. We examine two-dimensional light scattering patterns obtained at multiple wavelengths using a single CCD camera with minimal cross talk between channels. The integration of the approach with a single CCD camera assures that data is acquired within the same solid angle and orientation. Since the optical size of the scattering particle is inversely proportional to the illuminating wavelength, the spectrally resolved scattering information provides characteristic information about the airborne particles simultaneously in two different scaling regimes. The simultaneous acquisition of data from airborne particulate matter at two different wavelengths allows for additional degrees of freedom in the analysis and characterization of the aerosols. Whereas our previous multivariate analyses of aerosol particles has relied solely on spatial frequency components, our present approach attempts to incorporate the relative symmetry of the particledetector system while extracting information content from both spectral channels. In addition to single channel data, this current approach also examines relative metrics. Consequently, we have begun to employ multivariate techniques based on novel morphological descriptors in order to classify “unknown” particles within a database of TAOS patterns from known aerosols utilizing both spectral and spatial information acquired. A comparison is made among several different classification metrics, all of which show improved classification capabilities relative to our previous approaches.

The main bioprocess variables that are continuously measured are pH, dissolved oxygen (DO), and dissolved car- bon dioxide (DCO₂). Less common variables are redox, concentrations of substrate and product concentrations, product activity, etc. Recently, pH and DO have been measured using optical chemical sensors due to their small form factor and convenience in use. These sensors are typically interrogated using a lab grade spectrometer, or with the help of a low-cost, tailor-made optoelectronic transducer that is designed around the optical sensor. Recently, we proposed a new class of optoelectronic transducers that are capable of monitoring several different optical sensors without the need to switch the optics or hardware when changing the type of sensor. This allows flexibility closer to the lab-grade devices at a price point of a dedicated sensor.

In this work, we have demonstrated a universal optical platform capable of monitoring pH or DO sensors. It uses the principle of ratio-metric fluorescence measurements for pH and fluorescence lifetime measurements for DO. The platform is capable of seamlessly switching between these two modes. It is also capable of auto recognition of the sensor type. The platform can operate both with patch-type or fiber optic type of sensors. The platform has measurement accuracy of about 0.08 pH units and approximately 5 % air saturation with oxygen. Additionally, an approach to obtain identical calibrations between several devices is presented.

The described platform has been tested in actual bioprocesses and has been found adequate for continuous bioprocess monitoring.

This work presents an agent-based mathematical model to simulate the aggregation of carp, a harmful fish in North America. The referred mathematical model is derived from the following assumptions: (1) instead of the consensus among every carps involved in the aggregation, the aggregation of carp is completely a random and spontaneous physical behavior of numerous of independent carp; (2) carp aggregation is a collective effect of inter-carp and carp-environment interaction; (3) the inter-carp interaction can be derived from the statistical analytics about large-scale observed data. The proposed mathematical model is mainly based on empirical inter-carp force field, whose effect is featured with repulsion, parallel orientation, attraction, out-of-perception zone, and blind. Based on above mathematical model, the aggregation behavior of carp is formulated and preliminary simulation results about the aggregation of small number of carps within simple environment are provided. Further experiment-based validation about the mathematical model will be made in our future work.

Publisher’s Note: This paper, originally published on 5/13/2015, was replaced with a corrected/revised version on 7/1/2015. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.

Plants exhibit complex responses to changes in environmental conditions such as radiant heat flux, water quality, airborne pollutants, soil contents. We seek to utilize the natural chemical and electrophysiological response of plants to develop novel plant-based sensor networks. Our present work focuses on plant responses to high-energy radiation – with the goal of monitoring natural plant responses for use as benchmarks for detection and dosimetry. For our study, we selected a plants cactus, Arabidopsis, Dwarf mango (pine), Euymus and Azela. We demonstrated that the ratio of Chlorophyll a to Chlorophyll b of the leaves has changed due to the exposure gradually come back to the normal stage after the radiation die.

We used blue laser-induced blue fluorescence-emission spectra to characterize the pigment status of the trees. Upon blue laser excitation (400 nm) leaves show a fluorescence emission in the red spectral region between 650 and 800nm (chlorophyll fluorescence with maxima near 690nm and 735 nm). Sample tree subjects were placed at a distance of 1m from NIST-certified 241AmBe neutron source (30 mCi), capable of producing a neutron field of about 13 mrem/h. This corresponds to an actual absorbed dose of ~ 1 mrad/h.

Our results shows that all plants are sensitive to nuclear radiation and some take longer time to recover and take less. We can use their characteristics to do differential detection and extract nuclear activity information out of measurement results avoid false alarms produced environmental changes. Certainly the ultimate verification can be obtained from genetic information, which only need to be done when we have seen noticeable changes on plant optical spectra, mechanical strength and electrical characteristics.

This work presents a novel, fast response time, plastic optic fiber (POF) biosensor to detect Escherichia coli. Different forms of probes in U-shaped format were tested: U-shaped with different radii, coil-shaped and meander-shaped. In the calibration process we used solutions of sucrose for obtaining refractive indexes (RI) in the range 1.33 – 1.39 RIUequivalent of water and bacteria, respectively. The POF probes were functionalized with antibody anti-Escherichia coli serotype O55 and tested with bacteria concentrations of 10⁴, 10⁶ and 10⁸ colonies forming unities/mL (CFU/mL). The optoelectronic setup consists of an 880 nm LED connected to the U-shaped probe driven by a current source controlled by an Arduino Microcontroller. At the opposite fiber end, the light received by a photodetector is amplified and read by the A/D port of the microcontroller. The output voltage decreases as the external RI increases, accordingly to the bacteria that is captured by the antibody fixed in the biosensor. The paper presents results obtained with the different shapes of probes tested with the same setup and biochemical protocol. In conclusion the system shows good capabilities of having concentration measurements results in less than 10 minutes with uncertainty of 10^-4 RIU enabling a future capacity to read concentration of 10³ CFU/mL.

We have demonstrated airborne lidar possessing spectral resolution λ/Δλ ≥ 1000. Its ultraspectral resolution is provided by the dual polychromator based on large-sized stigmatic holographic gratings. The lidar was tested in a real-life flight conditions at the transcontinental gas pipeline. It has performed aero search of leaks and measurements of the leaked gas concentration.

Over the past 100 years, the rate of temperature in the Arctic increases almost twice higher than the average rate of warming of the planet. Identifying methane anomalies responsible for the temperature increase, by hiking trails in the Arctic requires great human labor. It is necessary to use lidar methods for search and identification of methane from permafrost. Necessary to create a Raman lidar for monitoring of emissions of methane hydrate from the permafrost. Hyperspectral resolution would resolve the isotope shifts in the Stokes spectra, thereby to determine the isotopic composition of methane ratio C¹⁴/C¹² CH₄ carbon emissions and identify the source for study (permafrost or oil deposits)

There are already significant amounts of hazardous radioactive substances in the world. It, potentially, leads to a major damage and contamination of large areas. Laser sensing can serve as a highly effective method of searching and monitoring of radioactive contamination. We developed a laser system to detect accidental leakage of radioactive materials. Methods of fluorescence spectroscopy and Raman spectroscopy allow to detect a concentration of uranyl U235O2 and U238O2 at 500 ppb, and Sr90 and Cs137 at the level of 1 ppm at 100 m distance from the object.

New chemical sensing method on the basis of surface optical sensitization was proposed. High grade sensitivity of approach presented is determined by applying of surface plasmon resonance excitation in attenuated total reflection geometry. It was demonstrated of method working with arsenazo III in gas phase. Atomic-force microscopy images of silver halide crystals under surface optical sensitization by arsenazo III were obtained.

In recent years recycling is gaining a key role in the manufacturing industry. The use of recycled materials in the production of new goods has the double advantage of saving energy and natural resources, moreover from an economic point of view, recycled materials are in general cheaper than the virgin ones. Despite of these environmental and economic strengths, the use of recycled sources is still low compared to the raw materials consumption, indeed in Europe only 10% of the market is covered by recycled products. One of the reasons of this reticence in the use of secondary sources is the lack of an accurate quality certification system. The inputs of a recycled process are not always the same, which means that also the output of a particular process can vary depending on the initial composition of the treated material. Usually if a continuous quality control system is not present at the end of the process the quality of the output material is assessed on the minimum certified characteristics. Solving this issue is crucial to expand the possible applications of recycled materials and to assign a price based on the real characteristic of the material.

The possibility of applying a quality control system based on a hyperspectral imaging (HSI) technology working in the near infrared (NIR) range to the output of a separation process of PVC cable wastes is explored in this paper. The analysed material was a residue fraction of a traditional separation process further treated by magnetic density separation. Results show as PVC, PE, rubber and copper particles can be identified and classified adopting the NIR-HSI approach.

The increasing threat of an intentional (attack) or accidental release of toxins, in particular chemical toxins, including chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) has increased public fear. The major problem in such attacks/accidents is to detect toxins present in very low levels. Indeed, several detection techniques are currently being used for the same. However, none of them meet the most critical requirements of a RISE (Rapid, Inexpensive, Simple and Effective) detect-to-protect class of biosensors. To address this critical demand our group has developed a prototype lab-on-a-chip (LOC) using a colloidal silver-based, surface-enhanced Raman spectroscopy (SERS)-linked immuno-sensor assay (SLISA). The LOC-SLISA was tested for the measurement of RAD54, a stress-marker protein expressed by yeast in response to hydrogen peroxide (H2O2), a toxin in the EPA priority list of chemical toxins. We found SLISA has good correlation in accuracy with the traditional ELISA technique and outperforms the latter by being rapid and easy-to-use. SLISA is more sensitive, provides qualitative information on immuno-sensor’s chemical characterization and antigen-antibody binding, and allows direct detection with minimal or no chance of uncertainty, which is a stringent limitation of all label-based biosensor technologies including ELISA. For translational significance of our work, we correlated our results to U.S. EPA (environmental protection agency) defined risk exposure guideline levels of H2O2 to validate the commercial potential of our on-chip SLISA. The label-free, cell-based and RISE detection offered by SERS can allow development of biomedical and environmental sensor technology (BEST) needed for direct, rapid and continuous monitoring of human health and environment

Segmentation and identification of compounds or materials existing in a scene is a crucial process. Hyperspectral sensors operating in different regions of the electromagnetic spectrum are able to quantify spectral characteristics of materials in different states. Due to the fact that some chemical compounds in gas state have insignificant light reflectance characteristics in visible region of the spectrum, imaging sensors operating in infrared regions are needed to sense energy absorbency characteristics of these compositions. The present study proposes a novel method for detection of flammable gases in long-wave infrared hyperspectral images. Proposed method begins with Black-Body radiation curve compensation. Since a priori information regarding the compounds in the scene is not always available, endmember spectral signatures are extracted with VCA hyperspectral unmixing algorithm. Afterwards, endmember signatures are matched with infrared energy absorbance signature of the target gas obtained from NIST (National Institute of Standards and Technology) Material Measurement Laboratory. Finally, concentration of target signature at each image pixel is detected by means of endmember abundance maps. The performance of the approach is compared with that of similarity measure based gas detection methods. It is observed that the proposed technique removes the need for an external threshold setting while providing better resolvability of the gasses.

In this paper, the concept of a micro ring resonator formed of waveguides in off-the-shelf polymers is presented. Extensive simulations were performed to determine appropriate dimensions for the waveguide and the design of ring and coupling zone as well as for the estimation of losses. Based on the calculated parameters, a first polymer ring resonator was realized using microscope projection lithography.

Nonstandard and home-made explosives always pose a considerable threat for security forces in terms of their practically unlimited variability, both in composition and in construction of explosive devises. Electron microscopy – SEM with EDS/WDS is one of the key techniques for an analysis of non-standard explosives and post-blast residues. If the amount of materials allows it, a number of other analytical techniques are utilized, such as XRD that is capable of a direct phase identification of a crystalline substance, namely in mixtures. TLC has constantly proved itself useful for laboratory screening. Furthermore, combinations of FTIR, Raman spectrometry, LC MS, GC MS, XRF, micro XRF and other ones are applied. In the case of identification of post-blast residues, where an investigation is often conducted at the level of separate microscopic particles, the role of SEM is unsubstitutable, whereas the analysis of the organic phase from these often sporadic microparticles has been infeasible until recently. One of the very interesting options appears to be Raman spectrometry technique, which is nowadays obtainable as a supplement to SEM EDX. Newly available is the device that is fully confocal, SEM keeps full functionality and scan range, very high resolution (for green laser resolution 360nm FWHM; 430nm Rayleigh), it is fitted with high quality objective lens, enhances mapping through Raman spectrometry in a volume 250μm x 250μm x 250μm by piezo driven scanner (capacitive feedback linearized) and obtaining a high quality white light image (250μm x 250μm) immediately in the SEM chamber. This technique is currently undergoing intensive testing and it seems that the method could significantly help to address issues with the analysis of organic phases in electron microscopy not only in the case of post-blast residues and explosives.