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This paper examines infrared spectroscopic effects for the standoff detection of an explosive material, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), inkjet printed on an aluminum surface. Results of a spectroscopic study are described, using multiple optical setups. These setups were selected to explore how variations in the angles of incidence and collection from the surface of the material result in corresponding variations in the spectral signatures. The goal of these studies is to provide an understanding of these spectral changes since it affects standoff detection of hazardous materials on a reflective substrate. We demonstrate that variations in spectral effects are dependent on the relative surface concentration of the deposited RDX. We also show that it is reasonable to use spectroscopic data collected in a standard laboratory infrared spectrometer outfitted with a variable angle reflectometer set at 0° as reference spectra for data collected in a standoff configuration. These results are important to provide a systematic approach to understanding infrared (IR) spectra collection using standoff systems in the field, and to allow for comparison between such data, and data collected in the laboratory. Although the precise results are constrained to a specific material system (thin layers on a reflective substrate), the approach and general discussion provided are applicable to a broad range of IR standoff sensing techniques and applications.

Recent years have seen the increasing use of noninvasive respiratory support in preterm infants with the aim of minimizing the risk of mechanical ventilation and subsequent bronchopulmonary dysplasia. Respiratory distress syndrome is the most common respiratory diagnosis in preterm infants, and is best treated by administration of surfactant. Until recently, this has been performed via an endotracheal tube using premedication, which has often included opiate analgesia; subsequently, the infant has been ventilated. Avoidance of mechanical ventilation, however, does not negate the need for surfactant therapy. Less invasive surfactant administration (LISA) in spontaneously breathing infants is increasing in popularity, and appears to have beneficial effects. However, laryngoscopy is necessary, which carries adverse effects and is painful for the infant. Conventional methods of premedication for intubation tend to reduce respiratory drive, which increases the likelihood of ventilation being required. This has led to intense debate about the best strategy for providing appropriate treatment, taking into account both the respiratory needs of the infant and the need to alleviate procedural pain. Currently, clinical practice varies considerably and there is no consensus with respect to optimal management. This review seeks to summarize the benefits, risks, and challenges associated with this new approach.

Sugarcane on one side considered important for crop diversification and important for human civilization while on other sugar industry is facing a long term losses in terms of monetary issues. Moreover, farmer is also not clear about which techniques is to adopt for practising the sugarcane cultivation for precision farming. Therefore, range of new sugarcane cultivation technologies pertaining to its cultivars, fertilization, weed control, insect-pest and disease control needs to be invented and recommended to the cane farmers. Precision farming is an approach where inputs are utilised in precise amounts to get increased average yields, compared to traditional cultivation techniques. Adoption of precision agriculture in sugarcane has been slow due to a wide range of uncertainties and conflicting opinions. There is need to reduce cost of cultivation and to improve the canes yield and quality by adopting precision sugarcane techniques. In developing countries like India, Pakistan etc. precision agricultural techniques if adopted, is a powerful tool and should be started with a basic, affordable and effective integration of technologies and practices. Present article aims to review published and unpublished information on precision sugarcane farming must be applied for improving the cane yield and quality so as to improve livelihoods of the cane farmers.

Studies on the reflectance spectra of different mixtures of sand and silt were performed in the infrared spectral region of 7–25 µm to explore the behavior of a second reststrahlen band occurring between 17 and 25 µm with respect to different mixtures of sand and silt. The reflectance spectrum of all samples exhibited reststrahlen bands within both the long wavelength infrared (LWIR) and the very long wavelength infrared (VLWIR) regions of the reflectance spectrum. Results demonstrate that both LWIR and VLWIR reststrahlen bands increase in area as the fraction of sand increases to 80%. More importantly, the data demonstrate that the VLWIR reststrahlen band, like that in LWIR, exhibits a significant and reproducible decrease in reflectivity for mixed soil versus weathered soil.

Mid-wavelength infrared (MWIR, λ = 3 – 5 μm) materials are of great importance due to their applications in optical sensors and devices for military, industry, and non-invasive medical diagnostics. Specifically, MWIR polarimetry are used in biometric recognition and camouflaged detection. Recently, sulfur based organically modified chalcogenides (ORMOCHALC) polymers have been utilized to fabricate MWIR polarizers with competitive extinction coefficient to commercial polarizers, which are mostly made of expensive, brittle, and heavy inorganic materials. On the other hand, to adjust or reinforce the refractive index of the polymer, the chalcogenide content (i.e., sulfur, selenium) needs to be increased, which may result in adverse effects on the thermomechanical characteristics, including Young's modulus and lower glass transition temperature. This reduced thermomechanical stability compromises the structural integrity of ORMOCHALC-based optical devices. In this study, an ORMOCHALC polymer, poly(S–r–DIB), was reinforced with the zinc sulfide (ZnS) nanoparticles to simultaneously improve the refractive index and the thermomechanical properties. The addition of 20 wt% ZnS nanoparticles improves the pure polymer's glass transition temperature (Tg) from 9.6 °C to 31.4 °C, and the refractive index by Δn= 6.58 %. Then, subwavelength wire-grid polarizers were fabricated based on the pure ORMOCHALC first by a simple thermal imprinting method followed by metal deposition. The resulted MWIR polarizer showed a high extinction coefficient which is comparable with commercial polarizers. However, the structural integrity of the polarizers was compromised due to lower glass transition temperature. Finally, finite element analysis was conducted on the possible wire-grid polarizer fabrication utilizing optically and mechanically reinforced composites, as demonstrated in this study. If fabricated, these nanoparticles reinforced polarizers will possess superior structural integrity compared to ORMOCHALC polarizers. Moreover, these polarizers show a spectral selectivity as the transmission curve's resonance wavelength depends on the composite's refractive index, which is tunable by controlling the nanoparticles content. The resonance peak redshifted from 3.12 μm to 3.3 μm for the pure polymer to 20% ZnS reinforced ORMOCHALC polarizer. The extinction coefficient of the polarizer also improved in multiple wavelength bands in the MWIR. These polarizers with superior extinction coefficient, spectral selectivity, and improved thermomechanical stability demonstrate a broader prospect in MWIR optics.

We report the latest progress on fabrication of rare earth doped single crystal yttrium aluminum garnet (YAG) core/undoped YAG cladded fibers. Rare-earth doped single crystal core fibers were grown with laser heated pedestal growth methods. In a second step, epitaxial methods were used to grow a single crystalline undoped YAG cladding onto the core fiber. Hydrothermal and liquid phase epitaxy methods utilize the core doped fiber as the seed. X-ray diffraction of cladding reveals an equilibrium (110) morphology. Energy-dispersive X-ray spectroscopy analysis shows there is minimal diffusion of rare-earth dopants into the cladding structure. The use of scandium doping is shown to substitute at the Al3+ site, thereby allowing an additional tunability of refractive index of core structure material besides conventional Y3+ site dopants. The use of these epitaxial growth methods enables material compatibility, tuning of refractive index, and conformal growth of cladding structures onto core fibers for optical devices.

NRL is developing new materials that transmit across wide wavelength ranges and will present recent results. MILTRAN is a new rugged optical ceramic that transmits visible through LWIR and is 3.5 times harder than ZnS and is well suited as an internal lens element. NRL-series moldable glasses transmit SWIR through LWIR and may be bonded to each other in an adhesive-free thermal process. NRL-200-series glasses transmit visible through MWIR and expand the glass map for multispectral lens designs. These new materials enable greater flexibility for designers of lenses for advanced defense applications and potentially reduce the size, weight and cost of next-generation optics.

At the Naval Research Laboratory, we have developed several rugged oxide materials for optics applications. These materials include cubic sesquioxides (Y2O3 and Lu2O3) and spinel ceramics which transmit in the UV, visible, SWIR and MWIR wavelength region. These materials have superior mechanical and optical properties compared to the currently used materials on various Navy / DoD systems. The transparent and rugged ceramics are fabricated by the Hot press/HIP method using ultra-pure powder synthesized in-house and the resulting ceramics typically have excellent optical quality with no birefringence. In this paper, we present the optical properties of these rugged transparent ceramics and lens designs using these materials will be also discussed.

Solid-state laser based on Er-doped gain medium, is a promising approach to designing directly diode-pumped eye-safer pulsed sources in the spectral range ~1.45-1.65 m. This approach allows obtaining spectrally broad laser outputs with high efficiency, if required by application (e.g., anti-speckle), without resorting to nonlinear conversions. All-fiber laser solutions for high PRF pulsed laser sources is deemed desirable, but it may result in high design complexity, especially on the Master Oscillator (MO) end, hence it is not appropriate in cases where low complexity is of major importance. Presented here are the results obtained with pulsed hybrid MOPA comprised of a bulk crystalline Er-based MO and Er-doped fiber amplifier.

We computationally investigate random motheye structures for fused silica from 0.4 to 1.0 μm. We found that increasing the randomness of the diameter and height can further suppress the reflection at the air-glass interface.

This guest editorial introduces the Special Section on Advances in Gradient Index Optics Technology.

We present a method of post-deposition tuning of the optical properties of thin film dielectric filters and mirrors containing chalcogenide glass (ChG) layers by thermally adjusting their refractive index. A common challenge associated with the use of ChG films in practical applications is that they suffer from slight run-to-run variations in optical properties resulting from hard-to-control changes in source material and deposition conditions. These variations lead to inconsistencies in optical constants, making the fabrication of devices with prescribed optical properties challenging. In this paper, we present new work that takes advantage of the large variation of a ChG films’ refractive index as a function of annealing. We have carried out extensive characterization of the thermal index tuning and thickness change of arsenic selenide (As2Se3) ChG thin films and observed refractive index changes larger than 0.1 in some cases. We show results for refractive index as a function of annealing time and temperature and propose a model to describe this behavior based on bond rearrangement. We apply thermal refractive index tuning to permanently shift the resonance of a Fabry-Perot filter and the cutoff wavelength of a Bragg reflector. The Bragg reflector, consisting of alternating As2Se3 and CaF2 layers, exhibits high reflectance across a ∼550 nm band with only five layers. Modeling results are compared with spectroscopic measurements, demonstrating good agreement.

We demonstrate efficient pulse-energy extraction from a partly-quenched erbium-doped aluminosilicate fiber amplifier. This has a high erbium-concentration, which allows for short devices with reduced nonlinear distortions, but which also results in partial quenching and thus significant unsaturable absorption, even though the fiber is still able to amplify. Although the quenching degrades the average-power efficiency, the pulse energy remains high, and our results point to an increasingly promising outcome for short pulses. Furthermore, unlike unquenched fibers, the conversion efficiency improves at low repetition rates, which we attribute to smaller relative energy loss to quenched ions at higher pulse energy. A short (2.6 m) cladding-pumped partly-quenched Er-doped-fiber with 95-dB/m 1530-nm peak absorption and saturation energy estimated to 85 {\mu}J, reached 0.8 mJ of output energy when seeded by 0.2-{\mu}s, 23-{\mu}J pulses. Thus, according to our results, pulses can be amplified to high energy in short highly-Er-doped fibers designed to reduce nonlinear distortions, at the expense of average-power efficiency, Comment: Manuscript submitted to Optics Express. Peer-Review extended up to March, 31

There is a need for robust optical materials with very low reflectivity and high transmission in the visible and infrared wavelength regions for use with high energy lasers. High power continuous-wave (CW) and high pulse energy laser optical systems can suffer damage from untreated optics due to undesirable Fresnel reflections. Sub-wavelength antireflective structured surfaces (ARSS) have been shown to have a higher laser-induced damage threshold than traditional AR coatings, which are necessary for high energy (multi-kW) laser components. Previous optimization of the etching process for ARSS on fused silica, among other optical materials, has yielded controlled and repeatable parameters, resultant from formation of varying depth and density profiles by randomly removing material from the surface. The “grass-like” boundaries result in gradient-index functionalities for incident optical beams, which simultaneously reduces reflection and increases transmission of the substrate. In this study, we investigate resultant optical properties of B270 Superwhite substrates, whose surfaces are modified using reactive ion etching, in order to enhance broadband transmission and lower reflectivity, thus increasing their utility for visible and near-infrared wavelength regions. We report results for ARSS fabricated directly onto the surface of 1” diameter, B270 Superwhite optical windows. Initial trials yielded single-side random ARSS (rARSS) treated samples with transmission enhancement of up to 3% from 400-1800 nm, nearing that of rARSS enhancement of fused silica, with maximum enhancement 80% that of the theoretical value between 700-900 nm.

NRL is developing new glasses that transmit within the visible to LWIR range for use in multispectral imaging. We had previously developed NRL glasses which transmit in 0.9 to > 12 µm in wavelength, with refractive index ranging from 2.38 to 3.17, to expand the glass map and provide compact solutions to multispectral imaging systems. These glasses were specifically designed to have comparable glass molding temperatures and thermal properties so that they can be laminated and co-molded into optics with reduced number of air-glass interfaces (lower Fresnel reflection losses). These NRL glasses also have negative or very low dn/dT, making it easier to athermalize the optical system. A set of NRL glasses can be diffused to make infrared graded index (IR-GRIN) optics. Our multispectral optics designs using these new materials demonstrate reduced size, complexity and improved performance. The glass database compatible with Zemax and CodeV is available for distribution. We are adding n

Rugged optics and window materials with good visible and IR transmission are needed for several sensing and imaging application. Some of the applications require very thick windows or windows in complex geometries, which impose additional limitations on material selection. Magnesium aluminate spinel (MgAl2O4), or spinel for short, is a rugged window material with excellent transmission in ultraviolet to midwave infrared (0.18 – 5.5 m) wavelengths. Spinel is comparable to sapphire and ALON in its ruggedness while having superior transmission near 5 m in wavelength. With its cubic crystal structure, spinel is isotropic unlike sapphire which is birefringent. We have been developing high optical quality spinel ceramics in different shapes and sizes. Current status of these efforts in making spinel windows in large sizes and conformal shapes for several imaging applications will be discussed.

A common challenge in metastructure fabrication is precisely tuning of the frequency of a device’s resonance. Slight variations in device dimensions or material properties can lead to a deviation in resonance frequency in comparison to design. We present a method of tuning a dielectric metastructure’s resonance by thermally adjusting the refractive index of a chalcogenide glass (ChG) material. Several characteristics of ChGs make them good candidates for use in dielectric metastructures. They exhibit high linear refractive indices, enabling high index contrast devices; they have large optical nonlinearities, making them useful for tunable devices and nonlinear frequency conversion; and they have wide transmission windows extending from the visible through the long-wave infrared. Recently, we have carried out extensive characterization of the index tuning of arsenic selenide (As2Se3) ChG thin films and observed refractive index changes larger than 0.1 in some cases. We use this refractive index change to permanently shift the resonance of a Fabry-Perot filter and the cutoff wavelength for a Bragg reflector. We then demonstrate thermal tuning to shift resonance positions for a metasurface (MS). We compare finite element modeling results with measurement results and show good agreement. This tuning mechanism has potential for use in MS devices where a precise resonance frequency is required.

We have studied the in-situ radiation-induced degradation and recovery of the output optical power of actively-pumped erbium-doped fiber amplifiers (EDFAs) pumped at both 980 and 1480 nm during and after radiation exposure. The EDFs have high Er concentrations corresponding to 20 – 60 dB/m peak Er3+ absorptionat 1.532 μm suitable for high power cladding-pumped applications. The fibers were made with a wide range of glass compositions, including the addition of specific dopants to reduce clustering and improve efficiency. Radiation tolerance of nanoparticle doped fibers is superior to those fabricated by solution doping. The effects of photo-annealing have been explicitly studied, and an nth-order kinetic model has been used to predict end-of-life degradation. More robust statistical kinetics modeling of accelerated lifetime data has been used to predict on-orbit performance in more realistic scenarios, such as Geosynchronous Earth Orbit.

We computationally varied the dimensions of cone-shaped motheye structures to optimize the transmission efficiency over a broad wavelength range. We show that optimized cone-shaped motheye structures can theoretically achieve > 99.5% transmission from 0.5 µm–2 µm.

We design and realize chalcogenide-based photonic quasicrystals enabling simultaneous phase matching of an arbitrary number of nonlinear optical processes in a single engineered nanostructure.

We computationally study two-layer motheye nanostructures fabricated on MgAl2O4 spinel ceramic windows. We investigated the parameters of the structure, including height, width, and shape, in order to optimize its power transmission efficiency over a broad bandwidth. We found a two-layer motheye structure in which the cones of the upper structure have a concave shape that can theoretically achieve more than 99.8% transmission at normal incidence in the wavelength range between 0.4 μm and 5.0 μm.

Color vision results from the interaction of retinal photopigments with reflected or transmitted visible light. The International Commission on Illumination (CIE) developed the CIE color-matching chart, which separates colors on the basis of the interaction of their spectral profiles with three retinal photopigments in the human eye. We report the development of an infrared chromaticity (CIE-IR) chart, which mimics the CIE chart, in order to discriminate between different chemicals on the basis of the interactions of their IR signatures with three different IR optical filters, instead of the retinal photopigments in the human eye. Our results demonstrate that the CIE-IR chart enables separation of different classes of chemicals, as the visible CIE chart does with color, except for those in the IR spectral region. Such results clearly show that the biomimetic sensing method based on human color vision is in fact a true analogue to color vision and that the proposed CIE-IR chart can be used as a classification method unique to this biomimetic sensing modality.

New, moldable IR glasses from NRL and Graded index (GRIN) optics enable simultaneous imaging across multiple wavebands including SWIR/MWIR/LWIR and offer potential for both weight savings and increased performance. Optical properties databases compatible with Zemax and CodeV will be presented and made available for users. Lens designs show the potential for significant SWaP reduction benefits and improved performance using NRL materials and IR-GRIN lens elements in multiband sensors. The SWaP and performance advantages of these materials will be presented.

Recent developments have shown that an optical filter-based sensing approach, inspired by human color vision, is capable of high-confidence discrimination between chemicals with similar infrared vibrational absorption bands. A key design point for this technique lies in the selection of the optical filters, which provide good discrimination between chemicals. Filter selection is also intrinsically tied to the classification method employed for the discrimination itself. Thus, it is imperative that the classification method or methods to be used are well understood and that mathematical means exist to compare the discrimination results provided by independent sets of optical filters. To meet this challenge, we are examining means to assign cost values to each set of optical filters for a given associated classification method. In this effort, the cost value used is the volume formed by three unique discrimination vectors. This method is developed from machine learning approaches, which define cost functions for stochastic optimization routines. We discuss multiple computational methods to discriminate between chemicals with similar infrared vibrational absorption bands using unique infrared (IR) tristimulus values for each chemical. These IR-tri-stimulus values are determined by the interaction with the chemical absorption bands and three individual optical IR band-pass filters. Methods to determine the associated cost for various selections of these IR band-pass filters and associated mathematical operations are described and compared for the computational methods. We discuss the methods employed to select the IR optical filters and discuss how the flexibility of this approach demonstrates the power of this biomimetic sensing method.

Detection of explosives on surfaces could potentially be achieved using handheld standoff optical sensors, providing rapid intelligence and safety to the warfighter or first responder. Recent work has shown the capability to discriminate various chemical vapors using a bioinspired or biomimetic detection system modeled on human color vision. This biomimetic system utilizes three overlapping broadband infrared optical filters to discriminate between various chemicals. Preliminary reflectance data of chemicals on surfaces indicate a capability for discrimination of target chemicals and interferents by analysis of biomimetic sensor output using novel analytical methods such as “Comparative Discrimination Spectral Detection” (CDSD). Transitioning this detection method to threats on surfaces at proximate standoff distances (~1 m) requires additional considerations including surface characteristics and angle of detection. This work explores sensor detection parameters for ammonium nitrate residue on aluminum surfaces of various roughnesses. Samples of the explosives component ammonium nitrate, NH4NO3, diluted at 10%, 5%, and 1% in DI water, were prepared by dropcasting onto aluminum coupons with four surface finishes: polished, brushed, extruded, and sandblasted. Surface roughnesses were measured. Single beam reflectance spectra (2 – 20 μm) were collected using a FTIR spectrometer over multiple independent angles of incidence and collection (15° - 80°). Multiple factors were analyzed including albedo, and potential sensor configurations. Characteristics for future MWIR and LWIR sensors, such as illumination power and detector sensitivity, are evaluated which enable chemical spectral identification across range of aluminum surface roughness for proximate standoff distances and different angles of incidence.

High power continuous-wave (CW) and high pulse energy laser optical systems can suffer damage from untreated optics due to undesirable Fresnel reflections. With high energy pulse lasers, traditional anti-reflection (AR) thin-film coated optics are susceptible to localized field enhancement regions, due to multiple boundaries, and experience laser induced damage on both entry and exit interfaces. Sub-wavelength anti-reflective structured surfaces (ARSS) have been shown to have a higher laser-induced damage threshold than traditional AR coatings. Previously published work detailed nanosecond-pulsed laser-induced damage on planar fused silica (FS) substrates with random ARSS (rARSS) treatment (λ=1064 nm). This study details and compares laser damage and fatigue testing of rARSS treated FS via continuous-wave, 2 kW irradiation (λ=1075 nm). Gaussian laser output was focused to ~ 60-μm-diameter (1/e2), to increase incident intensity, yielding a maximum power density of ~ 70.7 MW/cm2. Laser power and duration were controlled while monitoring the window’s optical transmission and entry/exit surface temperatures. CW durations at maximum power up to 5 min were used. Peak temperatures were recorded for untreated FS, as well as double side treated rARSS samples.

New moldable, infrared (IR) transmitting glasses from NRL and graded index (GRIN) optical materials enable simultaneous imaging across multiple wavebands including SWIR, MWIR and LWIR and offer potential for both weight savings and increased performance in optical sensors. Lens designs show the potential for significant SWaP reduction benefits and improved performance using NRL materials and IR-GRIN lens elements in multiband sensors.

Fiber lasers rely on clad pump architectures where double clad designs are used. Currently, polymers are used successfully as pump claddings on Yb-doped laser fibers. In order to transition to resonantly pumped fiber lasers at eye safer wavelengths, polymer pump claddings must have low absorption at those wavelengths. There is currently no suitable low index, low absorption, thermally stable, and high thermal conductivity polymer to act as a low-index coating. This work presents a new class of polymers, termed fluorinated polymer composites (FPCs), which possess improved thermal properties. The FPCs are fabricated by incorporating ceramic nanoparticles into fluorinated polymers. Ultimately, the FPCs could enable further use of fiber lasers at commonly used wavelengths, as well as at eye-safer wavelengths.

Orbital angular momentum (OAM) beams may create a new paradigm for the future classical and quantum communication systems. A majority of existing OAM beam converters are bulky, slow, and cannot withstand high powers. Here, we design and experimentally demonstrate an ultra-fast, compact chalcogenide-based all-dielectric metasurface beam converter which has the ability to transform a Hermite&ndash, Gaussian (HG) beam into a beam carrying an OAM at near infrared wavelength. Depending on the input beam intensity, the topological charge carried by the output OAM beam can be switched between positive and negative. The device provides high transmission efficiency and is fabricated by a standard electron beam lithography. Arsenic trisulfide (As 2 S 3 ) chalcogenide glass (ChG) offers ultra-fast and large third-order nonlinearity as well as a low two-photon absorption coefficient in the near infrared spectral range.

Arsenic triselenide (As2Se3) is of interest for use in dielectric metasurfaces for several reasons: It has a high linear refractive index, n=2.8, enabling high index contrast with its surrounding medium; it has an exceptionally high optical nonlinearity (n2 < 900 × that of silica) making it a good candidate for nonlinear metasurfaces; and its band gap of 1.8 eV and wide transmission window, spanning from approximately 1.5-14 μm, make it useful for applications in the shortwave infrared into the long-wave infrared. We discuss recent results in which we showed that unpassivated As2Se3 films degrade significantly under ambient conditions in the presence of light. We discuss the mechanism of this degradation and show that deposition of a thin (~10 nm) Al2O3 passivation layer, deposited via atomic layer deposition, together with preventing exposure to below-band gap light inhibits degradation. Finally, we fabricate initial As2Se3-based dielectric metasurfaces by writing features via a laser direct write system. For mid-wave to long-wave infrared applications, features with relevant sizes can be written using this technique. We measure resonances for these structures and compare to theoretical results.

Introduction: Diversity in drug response related to cardiovascular and other diseases is attributed to both genetic and non-genetic factors. However, there is a paucity of genetic information across ethnically and genetically diverse populations. Here, we have analyzed 20 SNPs from 12 pharmacogenomics genes in Punjabi Sikhs of Asian Indian origin (N= 1,616), as part of the Sikh Diabetes Study (SDS)/Asian Indian Diabetic Heart Study (AIDHS). Methods: Samples were genotyped using the Human 660W Quad Bead Chip panel (Illumina, Valencia, CA). We compared the allelic associations with poor metabolism (PM) phenotype across other HapMap populations. Results: Indians had a significantly higher frequency of CYP2C9*3 (12% SDS, 13% GIH (Gujarati Indians) vs. 5% in Europeans (CEU) (p genotype = 0.008) and ‘T’ allele of CYP4F2 (36%) SDS, (43%) GIH vs. (21%) in CEU (p genotype =7.8x10 -7 ); both associated with a higher risk of bleeding with warfarin. The PM phenotype of the CYP1A2*1F allele for slow metabolism of caffeine and carcinogens was significantly higher in Indians (SDS 43%, GIH 51%) compared to CEU 29% (p genotype =0.01). While the frequency of ‘T’ risk allele MTHFR (C677T) was significantly lower in Indians compared to Europeans (0.19 SDS, 0.16 GIH vs. 0.31 CEU), the low activity ‘C’ allele of MTHFR was strikingly higher in SDS (44%) compared to GIH (39%) and CEU (34%) (p genotype =4.9x10 -3 ). These variants in MTHFR affect the metabolism of cholesterol-lowering (statins), 5-fluorouracil, and methotrexate-based cancer drugs. Conclusion: This is a first large study reporting a significant ethnic difference in the frequency of PM phenotype in Indian Sikhs compared to other global populations. Our findings underscore the need for establishing a global benchmark by conducting pre-emptive genotyping in drug metabolizing genes before beginning therapeutic intervention.

This paper describes the application of a human color vision approach to infrared (IR) chemical sensing for the discrimination between multiple explosive materials deposited on aluminum substrates. This methodology classifies chemicals using the unique response of the chemical vibrational absorption bands to three broadband overlapping IR optical filters. For this effort, Fourier transform infrared (FT-IR) spectroscopy is first used to computationally examine the ability of the human color vision sensing approach to discriminate between three similar explosive materials, 1,3,5,-Trinitro-1,3,5-triazinane (RDX), 2,2-Bis[(nitrooxy)methyl]propane-1,3,-diyldinitrate (PETN), and 1,3,5,7-Tetranitro-1,3,5,7-tetrazocane (HMX). A description of a laboratory breadboard optical sensor designed for this approach is then provided, along with the discrimination results collected for these samples using this sensor. The results of these studies demonstrate that the human color vision approach is capable of high-confidence discrimination of the examined explosive materials.

Fiber design strategies for increased threshold of SBS and TMI are presented. We report a high efficiency erbium nanoparticle doped fiber incorporating acoustic guiding layers with a significantly reduced SBS gain coefficient.

To date, the performance of all polycrystalline photovoltaics is limited by their open-circuit voltage (Voc), an indicator of charge carrier recombination within the semiconductor layer. Thus, the successful implementation of high-efficiency and low-cost solar cells requires the control and suppression of nonradiative recombination centers within the material. Here, we spectrally and spatially resolve the photovoltage of polycrystalline thin-film Cu(In,Ga)Se2 (CIGS) solar cells. Micro-Raman and energy-dispersive X-ray spectroscopy maps obtained on the same grains showed that the chemical composition of the CIGS layer is very uniform. Surprisingly, we observed concurrent spatial variations in the photovoltage generated across the device, strongly indicating that structural properties are likely responsible for the nonuniform mesoscale behavior reported here. We build a tomography of the photovoltage response at 1 sun global illumination, mimicking the operation conditions of solar cells. Furthermore, we sp...

Quaternary sputtering is a promising alternative to more established deposition methods for the fabrication of Cu(In,Ga)Se2 (CIGS) thin films for photovoltaics (PV). In this technique, a single sputtering target containing all four constituents is employed to deposit the CIGS film. Quaternary sputtering offers several advantages over other deposition methods, including excellent uniformity over large areas, high material usage, and less reliance on toxic Se precursors such as H2Se. Despite these advantages, several drawbacks remain. To date, devices fabricated by quaternary sputtering without additional selenization have been limited in efficiency to about 11%, and realizing bandgap grading in order to match the performance of the best evaporated devices presents a challenge. We discuss the prospects for quaternary sputtering as a fabrication technique for CIGS and highlight areas of research that may result in improved performance. Target fabrication and usage is reviewed. We also present results for films and devices including data for the optical constants of sputtered CIGS. Some recent previously unpublished results, including a study of impurities in CIGS sputtering targets and the first demonstration of a CIGS device on a flexible glass substrate, are discussed

In order to mimic and enhance the properties of moth eye-like materials, nanopatterned fused silica was chemically modified to produce self-cleaning substrates that have anti-reflective and infrared transmissive properties. The characteristics of these substrates were evaluated before and after chemical modification. Furthermore, their properties were compared to fused silica that was devoid of surface features. The chemical modification imparted superhydrophobic character to the substrates, as demonstrated by the average water contact angles which exceeded 170°. Finally, optical analysis of the substrates revealed that the infrared transmission capabilities of the fused silica substrates (nanopatterned to have moth eye on one side) were superior to those of the regular fused silica substrates within the visible and near-infrared region of the light spectrum, with transmission values of 95% versus 92%, respectively. The superior transmission properties of the fused silica moth eye were virtually unchanged following chemical modification.

New moldable, infrared (IR) transmitting glasses and diffusion-based gradient index (GRIN) optical glasses enable simultaneous imaging across multiple wavebands including short-wave infrared, midwave infrared, and long-wave infrared, and offer potential for both weight savings and increased performance in optical sensors. Lens designs show potential for significant reduction in size and weight and improved performance using these materials in homogeneous and GRIN lens elements in multiband sensors. An IR-GRIN lens with Δn = 0.2 is demonstrated.

Sugarcane is an economically important crop and is cultivated throughout the world for its sugar and ethanol. Present sugarcane varieties are derived from inter-specific hybridization between Saccharum officinarum and Saccharum spontaneum, resulting in highly polyploid and aneuploid plants with chromosomes ranging from 80 to 120. This complex nature has hindered advances in marker assisted breeding of this crop. Though an array of methodologies have been adopted by different research groups from all over the world who have well established protocols for developing genetically modified (GM) sugarcane. Several genes of economic interest have been transformed in sugarcane, despite variable success in transgene integration and expression. Recently, genome editing approaches (the zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and CRISPR/Cas9 system) have opened new and unique opportunities for researchers to enhance crop production. However, as far as sugarcane is considered, there are still several challenges/constraints (large genome size, polyploidy, low transformation efficiency, transgene silencing and lack of high throughput screening techniques) ahead that deter sugarcane improvement through genetic engineering and need to be resolved to achieve a complete exploitation of the crop through these biotechnological tools. This review is an attempt to unravel the various sugarcane genomic approaches and their applications towards accelerating sugarcane improvement.

Until recently, there has been a strongly held belief on the part of neonatal and pediatric clinicians that outcomes for infants born close to term are not different from those of babies born at full term. In the last decade, however, this assumption has been challenged by reports suggesting that this is not correct, and highlighting differences in morbidity and mortality both in the short and long term. This has led to development of new terminology to more accurately reflect the impact of immaturity associated with birth at 32-33 weeks (moderately preterm) and 34-36 weeks (late preterm) of gestation. These babies account for around 5-7% of all births and more than 75% of the preterm births in developed countries, so this new recognition of the associated increase in adverse outcomes may have a substantial impact on health care services. This review article will discuss the changing perceptions and concepts of gestational age in the preterm population, and explore the recent and emerging evidence around neonatal, early childhood, school-age, adolescent and adult outcomes for babies who are born moderately preterm and late preterm. It highlights important neonatal and childhood morbidities and will summarize associated health care, developmental and educational problems of affected children. The implications for the provision of ongoing primary and secondary health care, educational and social support to this large and heterogeneous group of individuals will be discussed.

Optical beams with a phase term proportional to the azimuthal angle possess a singularity at the beam center and carry an orbital angular momentum (OAM). The OAM beams find important applications including the trapping and rotation of microscopic objects, atom-light interactions and optical communications. The OAM beams can be generated by spiral phase plates or spatial light modulators which are bulky. Recently, planar optical components including q-plates, arrays of nano-antennas and all-dielectric metasurfaces, have attracted significant attention. However, they lack reconfigurability, which means that once the components are fabricated, their functionality cannot be changed. In this work, we experimentally demonstrate a nonlinear metasurface-based beam converter which is designed to transform a Hermite-Gaussian beam to a vortex beam with an OAM in a transmission mode. The proposed converter is built of an array of nano-cubes made of chalcogenide(As2S3) glass. Chalcogenides offer several advantages for designing all-dielectric, nonlinear metasurfaces, including high linear refractive index at near-infrared wavelengths, low losses, and relatively high third-order nonlinear coefficient. In particular, reconfigurability is enabled by the intensity-dependent refractive index or Kerr nonlinearity. Input Hermite-Gaussian beam at low intensity transmitting through the metasurface acquired an OAM, while at high intensity, remained its original intensity and phase profile. The parameters of the reconfigurable metasurface were optimized and its functionality was verified using numerical simulation and in laboratory experiments. Compared to conventional metasurfaces, their nonlinear counterparts are likely to enable a number of novel devices for all-optical switching and integrated circuits applications.

There is a strong desire to reduce size and weight of single and multiband IR imaging systems in ISR operations on hand-held, helmet mounted or airborne platforms. NRL is developing new IR glasses that transmit from 0.9 to < 12 µm in wavelength, with refractive index ranging from 2.38 to 3.17, to expand the glass map and provide compact solutions to multispectral imaging systems. These glasses were specifically designed to have comparable glass molding temperatures and thermal properties so that they can be laminated and co-molded into optics with reduced number of air-glass interfaces (lower Fresnel reflection losses). These new NRL glasses also have negative or very low dn/dT, making it easier to athermalize the optical system. Our multispectral optics designs using these new materials demonstrate reduced size, complexity and improved performance. The glass database is now available for distribution. Some of the NRL glasses are also available commercially. This presentation will cover discussions on the new optical materials, multispectral designs, as well fabrication and characterization of new optics.

Graded index (GRIN) optics offer potential for both weight savings and increased performance but have until recently been limited to visible and NIR bands (wavelengths shorter than about 0.9 µm). NRL has developed glass-based IR-GRIN lenses compatible with SWIR-LWIR wavebands. Recent designs show the potential for significant SWaP reduction benefits and improved performance using IR-GRIN lens elements in dual-band, MWIR-LWIR sensors. The SWaP and performance advantages of IR-GRIN lenses in platform-relevant dual-band imagers will be presented.

In this paper, we review the recent progress on chalcogenide negative curvature fibers, including gaps to increase confinement, tube structures to suppress higher-order modes, parameters to decrease bend loss, and the experimental demonstration of chalcogenide negative curvature fibers. The advances in negative curvature fibers using chalcogenide glasses enable many applications in the mid-infrared region.