The JPEO-CBD, in conjunction with other members of the defense community, is actively assessing future system architectures for Major Defense Acquisition Programs (MDAPs) such as the Future Combat Systems (FCS). Sensors, networks and information superiority are key elements of FCS, and the JPEO will provide the critical capability that enables complete situational awareness of CB hazards. After a brief overview of the JPEO-CBD program, this paper discusses early insight into how FCS operations and platforms affect CB sensors. Key challenges will be highlighted, such as sensor/platform integration, broad spectrum detection, and sensor performance.

EX-EM fluorescence matrices from suspensions of 11 vegetative bacteria, 5 spores, and 14 interferents (fungi, pollens) were measured and cross-sections of the selected bacteria were calculated. The changes of fluorescence characteristics of vegetative cells during their sporulation and starvation to death as well as spores during germination are shown. Influence of culture media on emission spectra and rate of spores formation under starving conditions was examined. Analysis of the measured fluorescence characteristics shows that double- or multi-wavelenghts excitation can make it possible to distinguish between particular groups of biological material, i.e., spores, vegetative cells, proteins, and interferents.

In this paper we describe likely consequences of bioaerosol attacks, and we discuss the role of early warning systems to enable effective responses that minimize those consequences. We address the capabilities of currently available biological detection technologies to provide effective early warning protection. Finally, we describe a deployable networked array of point detectors for early warning protection, with built-in array processing and alarm suppression algorithms that minimize false positive detections.

The absorption spectra of BWA/CWA often heavily overlap with each other and with absorption spectra of harmless species. The traditional approach of spectral discrimination usually involves estimation of concentration of each constituent, wherein the first- and second derivatives are being used as the spectrum features and the linear relationship between these features and the concentrations is sought by, e.g., the partial least squares or principal component regression. These algorithms may not be suitable for real-time early warning detection of BWA/CWA in the gaseous/liquid environments, especially taking into account the inevitable presence of environmental constituents with unknown spectra. In this paper, we present a new approach suitable for ragged, real-time spectral discrimination. In this approach, we are using an independent component analysis (ICA) technique to unmix the mixture spectra into independent spectral components. In order to classify the components, we have developed a special feature extraction algorithm based on a complex wavelet transform. We have tested the procedure experimentally using a ragged fiber-optics spectrometer working in the NIR region (800 - 1000 nm), and mixtures of organic liquids. The obtained results clearly demonstrate the applicability of the proposed system to the early warning "trigger"-type detection suitable for real-time environmental monitoring.

Sarnoff Corporation and the Naval Research Laboratory, through support from HSARPA, are developing an automated, high throughput bio-aerosol physical enrichment system designed for use as part of a biological-threat protection system. The Biological Aerosol-Capture-Enrichment (BioACE) system is a bio-aerosol collection system that combines three unique technologies to create physically enriched aerosol samples that can be subsequently interrogated by any number of bio-threat detection systems for the presence of threat agents. An air-to-air concentrator uses an inertial separation technique to highly concentrate an aerosol sample presented to a dual wavelength ultra-violet laser induced fluorescence (UVLIF) optical trigger used to discriminate potential threat particles from non-threat particles conveyed in a collimated particle stream. This particle classification information is used to trigger an electrostatic deposition mechanism to deposit only those particles determined to be potential bio-threats onto a stainless steel substrate. Non-threat particles are discarded with the exiting airflow. A prototype laboratory system in which particle size dependent elastic scatter rater than fluorescence provides the triggering signal has been experimentally qualified. This paper will present a detailed overview of the prototype system and discuss the physical enrichment results achieved.

We demonstrate a compact system incorporating a 32-element linear array of ultraviolet (UV) light-emitting diodes (LEDs) to the in-flight fluorescence detection of aerosolized particles. Custom electronics manage a standalone system and enable real-time processing of spectral data, which is used to cue a miniaturized aerodynamic deflector for physical particle separation. This front-end system improves the prospects for many second-stage analysis methods by reducing the background particle burden and providing a suspicious-particle enriched sample. The performance of UV LED arrays as an excitation source is established by the ability to detect emission from NADH and tryptophan in aerosol samples. On-the-fly fluorescence collection, operation of a real-time spectral algorithm, and aerosol concentration is demonstrated by separating particles that exhibit a specific spectral feature from a background of otherwise fluorescing particles.

Ultra-violet fluorescence remains a cornerstone technique for the detection of biological agent aerosols. Historically, these UV based detectors have employed relatively costly and power demanding lasers that have influenced the exploitation of the technology to wider use. Recent advancements from the Defense Advanced Research Project Agency's (DARPA) Solid-state Ultra Violet Optical Sources (SUVOS) program have changed this. The UV light emitting diode (LED) devices based on Gallium Nitride offer a unique opportunity to produce small, low power, and inexpensive detectors. It may, in fact, be possible to extend the SUVOS technology into detectors that are potentially disposable. This report will present ongoing efforts to explore this possibility. It will present the Tactical Biological (TAC-BIO) detector as such a solution for low cost, low power, lightweight device for biological agent detection.

We present results of a measurement system designed for detecting the fluorescence spectrum of individual aerosol particles of biological warfare agents excited with laser pulses at wavelengths around 290 or 340 nm. The biological aerosol is prepared and directed into a narrow air beam. A red laser is focused on the aerosol beam and a trigger photomultiplier tube monitor the presence of individual particles by measuring the scattered light. When a particle is present in the detection volume, a laser pulse is triggered from an ultraviolet laser and the fluorescence spectrum is acquired with a spectrometer based on a diffraction grating and a 32 channels photomultiplier tube array with single-photon sensitivity. The spectrometer measures the fluorescence spectra in the wavelength region from 300 to 800 nm. In the experiment we used different simulants of biological warfare agents. These bioaerosol particles were excited by a commercial available gas laser (337 nm), or a laser (290 nm) that we have developed based on an optical parametric oscillator with intracavity sum-frequency mixing. In the analysis of the experiments we compare the measured signals (fluorescence spectra, total fluorescence energy and the scattered energy) from the individual bioaerosol particles excited with the two different ultraviolet wavelengths.

Optical chamber for aerosol particle fluorescence measurements is designed. With the designed chamber, UV-induced fluorescent spectrum of single particles can be measured. The design includes two-nozzle flow system, with sheath air flow and virtual impactor concentrator integrated into the chamber. The operation of the flow system was verified with computational fluid dynamics (CFD). The chamber is intended to be used with pulsed UV-laser source, and it includes triggering of the laser pulse to hit individual particles.

Time-resolved fluorescence was measured for 25 biological species of vegetative bacteria, spores, fungi and pollens using stroboscopic technique and UV LEDs (280 and 340 nm) as a source of excitation. For all the examined species, the fluorescence lifetime was described by double exponential kinetics. With excitation at 280 nm, the decay time of the slow component varies from 2.0 to 4.6 ns. The fast component varies from 0.4 to 1.1 ns and its relative amplitude is greater than measured in tryptophan solution, which is a result of strong fluorescence quenching. For excitation at 340 nm, the lifetimes of fluorescence components are 3-9 ns and 0.4-1.9 ns, respectively. Higher differences in decay times are observed for other groups, especially pollens, that is connected with higher number of fluorophores in this spectral range. In general, lifetimes and relative fractional contributions of components are various for particular biological species, however, they are not specific for one group, what causes difficulties in BWA classification with time-resolved fluorescence method. Evaluation of the decay curves using PCA method shows low similarity of species in groups of living bacteria and spores and strong influence of interferents is observed.

We are developing a submersible deep ultraviolet laser induced native fluorescence (UVLINF) instrument to detect and identify trace levels of chemicals of life and other organic chemicals in water column of lakes and ocean. The instrument can also measure and log temperature, pressure and conductivity of the ambient water environment. The instrument is solar-blind and can operate up to depths of few hundred meters. The proposed concept uses a 224.3nm laser to excite and measure fluorescence in multiple UV and visible wavebands as a function of depth in a body of water. These fluorescence measurements can then be interpreted to classify organic material discovered during submersion of the instrument. The fluorescence instrument has the advantage that very sensitive measurements can be made in microseconds so that vertical profiling of a body of water can be done rapidly. The instrument also can be used for fast analysis of water quality from different sources.

The Luminex xMAP^TM system couples bioassays with advanced digital signal processing and proprietary identification techniques to perform multi-analyte testing of up to 100 features in real time. The general configuration of an xMAP assay can be described as a suspension array where specific capture moieties are covalently coupled to the surfaces of internally dyed microspheres. Fluorescent dyes contained within the microspheres provide unique spectral characteristics allowing each microsphere set to be distinguished from all others in the multiplex. The target is labeled for fluorescent detection. Here we describe examples of rapid, multiplexed protein and nucleic acid analyses for infectious and biothreat agents that demonstrate the utility of the platform. Benefits of the system include speed, economy, flexibility, and advanced capabilities. The potential for simultaneous detection of tens, hundreds, and even thousands of protein and nucleic acid targets provides for simultaneous, rapid, sensitive, and specific molecular analyses.

Smiths Detection is developing sensors and integrated instruments for rapid detection and identification of airborne biological agents. A biosensor array has been developed that provides real-time detection and classification of microorganisms based on molecular recognition and fluorescence spectroscopy. This biosensor is being integrated with an identification instrument that is based on a novel approach for surface plasmon resonance and light scattering. This device can continuously monitor for up to 20 biological agents and provide identification in 15 minutes or less.

Ultraviolet (UV) imaging is a bright field technique that uses short wavelengths to yield higher resolution than a conventional imaging. The absorption of proteins at 280nm and DNA at 260nm gives additional contrast without staining. Combined with modern video equipment, these two facts render UV imaging a useful tool in live cell imaging whose popularity is low due to the high cost of the lenses and the UV sensitive camera required. The need of wavelengths selection by a monochromator is also a limitation. On the contrary, the new AlGaN based imagery is intrinsically very sensitive to UV and prevents the use of a spectroscope. It allows UV imaging at extremely low flux minimising damage for biological samples. In the frame of biological threat, security systems require label free biochips for rapid detection. Surface Plasmon Resonance (SPR) imaging is a standard method proposed for antibody / antigen recognition but the optical set-up based on reflection requires a large optical path, and detection is only efficient for biological compounds close to the surface. In case of cells or bacteria whose typical dimensions are larger, UV imaging is a compact and suitable method. The first experiments shows that absorption takes place even for extremely low quantity of DNA when chips are covered with dielectric mirror whereas scattering is the largest contribution to contrast in case of BK7 slides. In case of proteins deposition on reflecting slides, absorption is lower than for DNA for a given molecular weight but spots still exhibit large contrast.

Under a recent US Office of Naval Research University Affiliated Research Center (UARC) Basic Research Program we have begun a number of activities that we hope will enhance future ability to detect the presence of explosives vapors and residues. Here we present initial work on the development of a microfluidic system for a new point chemical sensor allowing the rapid, accurate, and specific detection of vapors emitted by explosive materials. We have already extensively tested a micromachined platform with external optical excitation and detection. Our new chemical approach is to create a receptor with high affinity and selectivity to nitro-explosives. A series of chemiluminescent molecular signaling systems are proposed that are specifically directed toward detection of TNT, PETN, RDX, HMX, and CL-20. These will be used in a new micromachined platform that integrates photodetectors directly into a micromachined micro-fluidic bead platform for detection of the chemiluminescent signals. By integrating photodetectors into the sidewalls of our chemical sensor array, in immediate proximity to the sensing microbeads, we can eliminate all external optics currently required for optical signal collection. This should allow a more compact and robust system to be constructed by integrating photodetection and fluidics into a single chip-based platform. Additionally, a concept of accessing a photodiode using inductive coupling, i.e. non-contact wireless reading, is introduced and demonstrated.

We demonstrate the performance of a novel long-wave infrared photoacoustic laser absorbance spectrometer for gas-phase species using an amplitude modulated (AM) quantum cascade (QC) laser and a quartz tuning fork microphone. Photoacoustic signal was generated by focusing the output of a Fabry-Perot QC laser operating at 8.41 μm between the legs of a quartz tuning fork which served as a transducer for the transient acoustic pressure wave. The QC laser was modulated at the resonant frequency of the tuning fork (32.8 kHz). This sensor was calibrated using the infrared absorber Freon-134a by performing a simultaneous absorption measurement using a 35 cm absorption cell. The NEAS of this instrument was determined to be (see equation in manuscript), and the fundamental sensitivity of this technique is limited by the noise floor of the tuning fork itself.

Emerging applications in Defense and Security require sensors with state-of-the-art sensitivity and capabilities. Among these sensors, the imaging spectrometer is an instrument yielding a large amount of rich information about the measured scene. Standoff detection, identification and quantification of chemicals in the gaseous state are fundamental needs in several fields of applications. Imaging spectrometers have unmatched capabilities to meet the requirements of these applications. Telops has developed the FIRST, a LWIR hyperspectral imager. The FIRST is based on FTIR technology to provide high spectral resolution and to enable high accuracy radiometric calibration. The FIRST, a man portable sensor, provides datacubes of up to 320x256 pixels at 0.35 mrad spatial resolution over the 8-12 μm spectral range at spectral resolutions of up to 0.25 cm^-1. The FIRST has been used in several field measurements, including demonstration of standoff chemical agent detection. One key feature of the FIRST is its ability to give calibrated measurements. The quality of the calibrated measurements will be presented in this paper. Sensitivity, spectral resolution and radiometric stability as obtained during field and laboratory measurements will be presented. Finally, images of chemical releases detected with the FIRST will be shown.

Optical characterization of nitride semiconductors and device testing of ultraviolet emitters and detectors comprised of these materials are employed in addressing the challenges faced in developing semiconductor-based, compact, low-cost, low-power-consumption biodetection systems. Comparison of time-resolved photoluminescence (TRPL) on UV LED wafers prior to fabrication with subsequent device testing indicate that the best performance is attained from active regions that exhibit both reduced nonradiative recombination due to saturation of traps associated with point and extended defects and concomitant lowering of radiative lifetime with increasing carrier density. Temperature and intensity dependent TRPL measurements on a new material, AlGaN containing nanoscale compositional inhomogeneities (NCI), show that it inherently combines inhibition of nonradiative recombination with reduction of radiative lifetime, providing a potentially higher efficiency UV emitter active region. In addition, testing of GaN avalanche photodiodes (APDs) on low defect density bulk GaN substrates indicates that for the first time GaN APDs with diameters as large as 50 microns exhibit reproducible gain greater than 1000. These results show promise for replacement of photomultipliers in biodetection systems.

A set of UV light-emitting diodes (LEDs) with the peak wavelengths ranging from 255 nm to 375 nm was applied for the investigation of spectral and decay-time fluorescence signatures in dry B. globigii spores and common airborne interferants (albuminous, epithelium, and cellulosous materials as well as aromatic hydrocarbons). The fluorescence decay signature was represented by a phase shift of the sinusoidal fluorescence waveform in respect of excitation provided by high-frequency modulated LEDs. The obtained data matrix was used for the optimization a bioparticle fluorescence sensor with a minimized number of excitation sources and detection channels and maximized discrimination ability of bioparticles against common interferants. Based on the optimization, a new concept for a UV LED based "detect-to-warn" bioparticle fluorescence sensor is proposed. The sensor contains a single deep-UV LED emitting at 280 nm that is harmonically modulated at a high frequency (of about 70 MHz) and a dual-channel fluorescence detector with the spectral windows peaked at 320 nm and 450 nm. The output parameters of the sensor are the ratio of the fluorescence intensity in the two windows and the phase shift of the fluorescence waveform in the 320-nm detection channel in respect of the excitation one. Such a sensing scheme has a smaller number of optical components and a potentially higher discrimination ability of bioparticles against common interferants in comparison with the conventional approach based on just fluorescence intensity measurement under dual-wavelength excitation (280 nm and 340 nm).

Optically-based chemical and biological sensors require optoelectronic devices with specific emission and detection wavelength ranges. Semiconductor optoelectronic devices applicable to this sensing are of particular interest due to their low power consumption, compact size, long lifetime, and low cost. We report the electrical and optical properties of deep UV p-i-n photodiodes (PDs) based on short period superlattices (SPSLs) of AlN/AlGaN. All device and test structures are grown by gas source molecular beam epitaxy with ammonia on sapphire and AlGaN/sapphire substrates. AlGaN/sapphire substrates were grown by stress controlled hydride vapor phase epitaxy (HVPE). The cutoff wavelength of PDs based on these SPSLs can be varied from 250 to 280 nm by changing the SPSL barrier/well thickness ratio. For mesa diodes with 150 μm diameter we obtain extremely low dark leakage current of ~ 3 pA/cm², and high zero-bias resistance of ~ 6 x 10¹⁴ Ω. A cutoff wavelength of 247 nm is obtained for these devices with four orders of magnitude rejection by 315 nm. We obtain a maximum responsivity of 60 mA/W.

Fluorescence induced by ultraviolet laser light has shown a strong potential to help detect and identify hazardous bioaerosols. After several demonstrations limited to standard 266 nm or 355 nm sources, recent developments emphasized the advantages of tunable excitation or time-resolved experiments to increase discrimination capabilities. Taking advantage of the recent availability of frequency converting crystals with unprecedented efficiency, we present a three-stage laser design suited to the generation of 500 picoseconds pulses of several microjoules ruggedly tunable from 290 to 350 nm.

We have recently presented a method that enables single molecule enumeration by transforming specific molecular recognition events at nanometer dimensions to micrometer-sized DNA macromolecules. This transformation process is mediated by target specific padlock probe ligation, followed by rolling circle amplification (RCA) resulting in the creation of one rolling circle product (RCP) for each recognized target. The transformation makes optical detection and quantification possible by counting the number of generated RCPs using standard epi-fluorescence or confocal fluorescence microscopes. We have characterized the performance of the epi-fluorescence and the confocal readout formats. Both formats exhibit a linear response of the number of counted objects as a function of starting circles, and the dynamic range is three orders of magnitude employing epi-fluorescence readout and four when using confocal. In the epi-fluorescence format flow rate has to be below 1 μl/min and flow variations are likely to be the limiting factor for precision. If the flow rate is above 3 μl/min the precision of the confocal readout format is limited only by Poisson counting statistics, due to the accurate volume definition of the confocal optics. The limit of detection in the confocal format was reduced by a factor of three by increasing the data acquisition rate by a factor of ten.

Human influenza viruses are common-acquired respiratory pathogens, influenza rapidly spreads around the world in seasonal epidemics. Methods of influenza viruses detection are based on application of spectroscopic and fluorescence technique. All of them couldn't visualize directly the influenza virus structure modifications, need few days for examination and consist many steps of operation. To avoid the disadvantages the new contact technique with high spatial resolution based on nematic liquid crystals (NLC) application was suggested. The free thin NLC layers applied on the surface under investigation and observed in polarizing microscope are being used in the science and high technologies for structural inhomogeneities detection on the surface of different materials. Simplicity, efficiency and high sensitivity have given an opportunity of universal NLC technique application in crystallography, mineralogy, metallography, thin film technology, medicine and biology. The new field of LC vision application in virus detecting and experimental results are discussed.