This PDF file contains the front matter associated with SPIE Proceedings Volume 8840, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

The most compute intensive part of a full optics simulation, especially including diffraction effects, is the Fourier transform between pupil and image spaces. This is typically performed as a two dimensional fast discrete transform. For a nearly radially symmetric system there are advantages to using polar coordinates, in which case the radial transform becomes a Hankel transform, using Bessel functions instead of circular functions. However, there are special difficulties in calculating and handling Bessel functions. Several solutions have been proposed. We present a hybrid Hankel transform which divides the domain, calculating a portion using Bessel function approximations but converting most of the domain into a one dimensional Fourier transform which can be handled by standard methods.

Ultra precise and stable gravimeters and gyrometers are highly demanded for various applications like fundamental physics, geophysics, navigation systems. Interferometry of Rubidium cold atoms requires high power, narrow linewidth, low frequency noise and highly reliable optical sources emitting at 780 nm. In this context, we developed basic bricks for realization of a distributed feedback (DFB) laser. On one hand, 100 μm broad area devices achieve at 20°C a continuous wave (CW) output power of more than 4 W per facet. On the other hand, we demonstrated excellent performances on Fabry-Perot ridge-waveguide lasers with a threshold current of 35 mA, emitting up to 120 mW per facet, in single lateral mode at 780 nm. We already achieved an output power of 20 mW with a small spectral linewidth of less than 1 MHz on a DFB laser. We present here the results on a new and systematic investigation of the low frequency noise of such laser structures, in order to better understand and improve their performances. By using an appropriate current source and very low noise voltage amplifier (10^-19 V²/Hz at 10 Hz), we can measure the intrinsic Terminal Electrical Noise (TEN), due to the fluctuations of the laser voltage. The measurements have been performed at low frequency (1Hz < f <100 kHz) and different laser currents (around the threshold current, above and at high laser current). On broad band area lasers, we obtained very low 1/f level noise (10^-13 V²/Hz at 1 Hz) due to optical gain fluctuations. The white noise(shot and thermal noise) level is about 10^-18 V²/Hz. The corner frequency between 1/f and white noise is about 3 kHz, which is a good result for this kind of structures. Electrical noise measurements will be interpreted by using lasers noise theory.

In this work, the evolution of the nth analytical solutions of traditional Raman equations including numerical simulation and experimental results is done. In the experiment an 8.6 Km single mode fiber was pumped with an ytterbium doped fiber laser system (FL) in CW regime at 1064-nm in a free running configuration. We showed that it is possible to obtain up to the nth power thresholds and maximum power for each Stokes by using compact analytical solutions such as first approximations in an arguably simple, quick process.

Two-dimensional compound gratings (2dCGs) are capable of π-radian difference phase resonances (PRs). Circulation and concentration of s- and p-polarized light incident on 2dCG metal structures are studied. In prior work, it has been shown that PRs can occur for s- and p-polarized light in one-dimensional compound gratings (ldCGs). In contrast, the structure studied in this work has two asymmetric holes in the unit cell, each filled with a material of high dielectric permittivity (Epsilon=l0.84) and can support PRs in 2dCGs in the spectral range from 8 to 12 GHz. Due to asymmetry within the system, the two apertures react differently to the incident light and support polarization dependent PRs that are resonantly excited within the apertures. It is shown that PRs occur in 2dCGs with similar characteristics of ldCGs, such as having narrow bandwidths, high Q values, and high concentrations of electromagnetic fields. However, PRs occurring on 2dCGs have a benefit of manipulating in more numerous ways as compared with ldCGs. As the incident light excites waveguide cavity modes, the fields in the corresponding neighboring cavities in 2dCGs are coupled by circulations of counter-propagating modes and the π-radian phase differences produce a concentration and narrowband inversion of the transmissivity/opacity. The dependencies of bandwidth and wavelength of the PRs on structural and material properties, polarization of the incident beam, as well as the Poynting vector fields are described. Applications include narrow bandwidth optical filters, light trapping, antireflection coatings, waveguiding structures, and electromagnetically induced transparency.

Image mosaic technique is widely used in a field of remote sensing research. However, in case of Geostationary Ocean Color Imager’s (GOCI’s) mosaic image which is consist of 16 slot images, the radiance level discrepancy was noticed in the cloudy circumstance next to each other slot when acquiring the imagery data in the low Sun elevation angle. We provided, in this study, the in-depth stray light analysis results in order to find out this discrepancy phenomenon, and performed to compare the stray light pattern via a bright target movement. Stray light analysis as the first step was completed with ray tracing technique based on ASAP program, and we suggested that unwanted radiations from the Earth bright target or the atmosphere such as cloud are major candidates of stray light in the problematic images. For embodying GOCI operational concept, we constructed the Integrated Ray Tracing model consisting of the Sun model as a light source, a target Earth model, and the GOCI optical system model. In the second step, we investigated the stray light pattern at each slot image including unwanted random source from out of field, and then constructed the simulated mosaic bias image reached at the detector plane. In the simulated bias, the ray path followed the procedures that light travels from the Sun and it is then reflected from the Earth section of roughly 2500km * 2500km in size around the Korea peninsula with 16 slots. Lastly, we analyzed stray light pattern in the third step for the real image environment acquired at UTC-03 16th, October, 2011. In addition, verification was performed to compare the difference among slot boundaries for moving bright target.

Veiling glare is a somewhat obsolete term referring to stray light from an in-field extended source bleeding into adjacent dark regions of the image. In most systems ghost reflections and scatter from the contaminated or imperfectly polished optical surfaces are the main culprits. Standard stochastic or deterministic methods for calculating scattered light from out-of-field sources are cumbersome in this domain. On the other hand, basic Monte Carlo ray tracing is straightforward. Its implementation in the GelOE optical engineering software is based on a fast hybrid physical-optics/geometricaloptics technique for surface scatter. However, a prohibitive number of rays are still required to get accurate results. Instead of the standard ray-splitting and importance-area modifications to make it more efficient, a much simpler one is proposed and then applied to a representative lens system, resulting in a 100 to 1000 fold reduction in the number of rays required for the same accuracy.

We have experimentally observed the revival of the dark core in the far field intensity distribution in optical vor­ tices after scattering through rotating ground glass plate. The diameter and darkness of the core is independent of the speed of the rotating ground glass plate. They depend on the spot size and azimuthal index of the beam incident on it. This shows that the spatial coherence of the scattered light is independent of the speed of the rotating ground glass plate. Our experimental results are in good agreement with the numerical results based on the theory given by Wang, Cai and Korotkova (Opt. Exp. 17, 22366 (2009)).

To define the ratio of the signal of the desired pixel and the noise of adjacent pixels, noise and signal sources are theoretically identified. While defining these values, atmospheric attenuation, losses at transmitting surfaces and wave characteristics of light are considered. For presentation purposes, a standard NATO target is chosen as source object. The model has been developed for a simple optical design which is intentionally left defective to better address effects of aberrations to signal to noise ratio of adjacent pixels especially caused by diffraction.

Aero-optic effects can have deleterious effects on high performance airborne optical sensors that must view through turbulent flow fields created by the aerodynamic effects of windows and domes. Evaluating aero-optic effects early in the program during the design stages allows mitigation strategies and optical system design trades to be performed to optimize system performance. This necessitates a computationally efficient means to evaluate the impact of aero-optic effects such that the resulting dynamic pointing errors and wavefront distortions due to the spatially and temporally varying flow field can be minimized or corrected. To this end, an aero-optic analysis capability was developed within the commercial software SigFit that couples CFD results with optical design tools. SigFit reads the CFD generated density profile using the CGNS file format. OPD maps are then created by converting the three-dimensional density field into an index of refraction field and then integrating along specified paths to compute OPD errors across the optical field. The OPD maps may be evaluated directly against system requirements or imported into commercial optical design software including Zemax® and Code V® for a more detailed assessment of the impact on optical performance from which design trades may be performed.

Micro- and nanostructures enable specific optical functionalities, which rely on diffractive effects or effective medium features, depending on pattern dimension and wavelength. Performance predictions of optical systems which make use of nanostructured materials require having an accurate description of these materials ready to hand within the optical design. At the one hand, nanostructure characteristics which result from rigorous electromagnetic modeling can be used for the optical design. At the other hand, manufactured nanostructures may deviate from their idealized geometry, which will affect the performance of the optical system, wherein these artificial structures will be used. Thus, detailed optical characterization of the micro- or nanostructure functionality is prerequisite for accurate optical design and performance prediction. To this end, several characterization techniques can be applied depending on the scope of the optical design, finally. We report on a general route to include all accessible and required optical information about the nanostructured material within a corresponding model of the nanostructure as a specific optical component which can be used within a ray-trace engine, finally. This is illustrated by a meta-material with asymmetric transmission properties in some more detail.

The performance metrics of many optical systems are affected by temperature changes in the system through different physical phenomena. Temperature changes cause materials to expand and contract causing deformations of optical components. The resulting stress states in transmissive optics can cause refractive changes that can affect optical performance. In addition, the temperature changes themselves can cause changes in the refractive properties of transmissive optics. Complex distributions of refractive indices that relate to the thermal profile, the thermo-optic refractive index profile, within the optical media can be predicted by the finite element method. One current technique for representing such refractive index profiles is through the generation of optical path difference (OPD) maps by integration along integration paths. While computationally efficient, this method has limitations in its ability to represent the effect of the index changes for rays associated with multiple field points and multiple wavelengths. A more complete representation of the thermo-optic refractive index profile may be passed to the optical analysis software through the use of a user defined gradient index material. The interface consists of a dynamic link library (DLL) which supplies indices of refraction to a user defined gradient index lens as ray tracing calculations are being performed. The DLL obtains its refractive index description from a database derived from the thermal analysis of the optics. This process allows optical analysis software to perform accurate ray tracing for an arbitrary refractive index profile induced by changes in temperature.

Advanced analytical software capabilities are being developed to advance the design of prototypical hardware in the Engineering Division at MIT Lincoln Laboratory. The current effort is focused on the integration of analysis tools tailored to the work flow, organizational structure, and current technology demands. These tools are being designed to provide superior insight into the interdisciplinary behavior of optical systems and enable rapid assessment and execution of design trades to optimize the design of optomechanical systems. The custom software architecture is designed to exploit and enhance the functionality of existing industry standard commercial software, provide a framework for centralizing internally developed tools, and deliver greater efficiency, productivity, and accuracy through standardization, automation, and integration. Specific efforts have included the development of a feature-rich software package for Structural-Thermal-Optical Performance (STOP) modeling, advanced Line Of Sight (LOS) jitter simulations, and improved integration of dynamic testing and structural modeling.

A multiphysics, high resolution simulation of an actively controlled, composite reflector panel is developed to extrapolate from ground test results to flight performance. The subject test article has previously demonstrated sub-micron corrected shape in a controlled laboratory thermal load. This paper develops a model of the on-orbit performance of the panel under realistic thermal loads, with an active heater control system, and performs an uncertainty quantification of the predicted response. The primary contribution of this paper is the first reported application of the Sandia developed Sierra mechanics simulation tools to a spacecraft multiphysics simulation of a closed-loop system, including uncertainty quantification. The simulation was developed so as to have sufficient resolution to capture the residual panel shape error that remains after the thermal and mechanical control loops are closed. An uncertainty quantification analysis was performed to assess the predicted tolerance in the closed-loop wavefront error. Key tools used for the uncertainty quantification are also described.

In imaging spectrometers it is important that both the image of the far-field object and the image of the slit be stable on the detector plane. Lenses and mirrors contribute to the motions of these images but motions of the diffraction grating also have their own influences on these image motions. This paper develops the vector equations for the images (spectra) of the diffraction grating and derives their optomechanical influence coefficients from them. The Ivory Optomechanical Modeling Tools integrates the diffraction grating into the larger optical imaging system and formats the whole system’s influence coefficients suitably for both spreadsheet and finite element analysis methods. Their application is illustrated in an example of a spectrometer exposed to both static and dynamic disturbances.

We are working to develop a comprehensive, integrated software framework and toolset to support model-based engineering (MBE) of laser weapons systems. MBE has been identified by the Office of the Director, Defense Science and Engineering as one of four potentially “game-changing” technologies that could bring about revolutionary advances across the entire DoD research and development and procurement cycle. To be effective, however, MBE requires robust underlying modeling and simulation technologies capable of modeling all the pertinent systems, subsystems, components, effects, and interactions at any level of fidelity that may be required in order to support crucial design decisions at any point in the system development lifecycle. Very often the greatest technical challenges are posed by systems involving interactions that cut across two or more distinct scientific or engineering domains; even in cases where there are excellent tools available for modeling each individual domain, generally none of these domain-specific tools can be used to model the cross-domain interactions. In the case of laser weapons systems R&D these tools need to be able to support modeling of systems involving combined interactions among structures, thermal, and optical effects, including both ray optics and wave optics, controls, atmospheric effects, target interaction, computational fluid dynamics, and spatiotemporal interactions between lasing light and the laser gain medium. To address this problem we are working to extend Comet™, to add the addition modeling and simulation capabilities required for this particular application area. In this paper we will describe our progress to date.

One of the most crucial techniques of laser warning system is to acquire the direction information from the laser threat. According to the low resolution of laser warning system with imaging mode, a new method for measuring laser incident direction which possessed higher resolution was proposed. This novel method was based on cylindrical lens group and linear IRFPA, and the laser incident direction was achieved by offset of line spot. It not only deduced the direction formulas, but also analyzed the resolution of measuring laser incident direction in detail. The simulation result shows that the FOV of this new kind of laser warning system could achieve ±16°; the azimuth resolution is up to 0.52° and pitch resolution is up to 0.017°; the resolution increases with incident angle. In addition, an experiment with visible light, single cylindrical lens, linear array CCD was done to verify this method and its advantage on resolution. The analysis of laser incident orientation resolution is significant to select suitable parameter of detector and demonstrate orientation resolution of system.

Automating surgery using robots requires robust visual tracking. The surgical environment often has poor light conditions where several organs have similar visual appearances. In addition, the field of view might be occluded by blood or tissue. In this paper, the feasibility of near-infrared (NIR) fluorescent marking and imaging for vision-based robot control is studied. The NIR region of the spectrum has several useful properties including deep tissue penetration. We study the optical properties of a clinically-approved NIR fluorescent dye, indocyanine green (ICG), with different concentrations and quantify image positioning error of ICG marker when obstructed by tissue.

FORMOSAT-5 is the first space program fully developed by National Space Organization (NSPO). The Remote Sensing Instrument (RSI) will provide spatial resolution of 2 meters in panchromatic band and 4 meters in multi-spectral bands. The optical system is composed of two reflective aspheric mirrors and spherical corrector lens set. CFRP structure is used for the optomechanical system to reduce mass. Although the telescope system can be well aligned on ground, the space thermal environment can result in thermal distortion of telescope system and impact the final image quality. Flight predictions of FORMOSAT-5 RSI were done to get the quantitative thermal distortion of mirrors and structural system. The system optical performance, i.e. MTF, was also derived by the optical model with the input from thermal distortion results, i.e. Zernike polynomials. RSI performance in space is location-dependent. Detailed analysis results and discussions are revealed in this paper.

The OSIRIS-REx Mission was selected under the NASA New Frontiers program and is scheduled for launch in September of 2016 for a rendezvous with, and collection of a sample from the surface of asteroid Bennu in 2019. 101955 Bennu (previously 1999 RQ36) is an Apollo (near-Earth) asteroid originally discovered by the LINEAR project in 1999 which has since been classified as a potentially hazardous near-Earth object. The REgolith X-Ray Imaging Spectrometer (REXIS) was proposed jointly by MIT and Harvard and was subsequently accepted as a student led instrument for the determination of the elemental composition of the asteroid's surface as well as the surface distribution of select elements through solar induced X-ray fluorescence. REXIS consists of a detector plane that contains 4 X-ray CCDs integrated into a wide field coded aperture telescope with a focal length of 20 em for the detection of regions with enhanced abundance in key elements at 50 m scales. Elemental surface distributions of approximately 50-200 m scales can be detected using the instrument as a simple collimator. An overview of the observation strategy of the REXIS instrument and expected performance are presented here.

When using interference wave front to detect density field, it is better to have an interference system which is small and compact so that different directions of wave fronts can be obtained to reconstruct the density field to be detected. A twodimensional CGLSI (Cross Grating Lateral Shearing Interferometer) system which consists of a two-dimensional cross grating and a two-dimensional order-selecting window used as a filter is presented in this paper. Lateral shearing interferogram of two orthogonal directions (X and Y) each other can be obtained by using this system. With the advantage of anti-vibration and no reference surface, lateral shearing interferometer is suitable to inhibit external environment disturbance. In this paper, analysis and simulations have been conducted on grating constant from geometrical optics and physical optics using Fresnel approximation method respectively based on lateral shearing rate, windows’ distance in two-dimensional order-selecting window and layout of the system which concludes the best option for grating constant is d = 25μm . The most optimized design of size and distance for windows in two-dimensional order-selecting window has been carried out on the basis that complex amplitude distribution can go through the filter so that there is no distortion on wave front. All designs have gone through computer simulation and fit into the requirements for the designs.

This paper propose a study of optical design of laser beam shaping optics with aspheric surface and application of genetic algorithm (GA) to find the optimal results. Nd: YAG 355 waveband laser flat-top optical system, this study employed the Light tools LDS (least damped square) and the GA of artificial intelligence optimization method to determine the optimal aspheric coefficient and obtain the optimal solution. This study applied the aspheric lens with GA for the flattening of laser beams using collimated laser beam light, aspheric lenses in order to achieve best results.