This PDF file contains the front matter associated with SPIE Proceedings Volume 11100, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

We present the results of analysis of a 6 in. diameter vacuum window. The design prevents contact between the metallic mounting cell and the glass window material, which can be a source of failure in the glass. The window transmits optical and infrared wavelengths for multi-baseline interferometry at the Navy Precision Optical Interferometer (NPOI). Our analysis investigates possible interactive contact with the mounting cell and consequent failure of the window. Our design philosophy is to avoid overconstraining the glass window and maintain integrity of the vacuum seal through diurnal and seasonal temperature changes. The objective is to create no additional crack nucleation sites or initiate cracking in the brittle material due to the mount design. The window is unconstrained laterally and free to expand radially. Furthermore, the glass is free to expand in the thickness direction over the expected temperature range. The lack of contact due to thermal expansion over a broad temperature range and bending stresses due to loading were calculated to ensure the integrity of the assembly. In this paper, we describe our design approach, method of analysis, results, and recommendations. Our analysis shows that a simply supported window can be designed to achieve no metal to glass contact.

Currently a number of manufacturers of opto-mechanical hardware offer mirror mounts that have features incorporated to reduce long term drift and reduce temperature induced mis-alignment. These designs tend to feature kinematic approaches and careful material selection to achieve improved results over prior designs. However, most of these designs still rely on springs and or other preload mechanisms and may not be suitable for harsh environments. In addition, most do not feature a common point of rotation about which the “tip” and “tilt” adjustments are made. In 2018 a mirror mount design was proposed that attempts to combine the convenience of some of the most common commercially available mounts with the long-term stability and rigidity required of a mount to be used in OEM applications. The proposed mirror mount featured a virtual pivot point, centered on the front surface of the mirror, and incorporated a novel clamping mechanism that allows the mechanism to be fully locked without disturbing the orientation relative to the base. In addition, the mount included features such as a low stress mirror mounting system and a multitude of mounting points to make the mirror mount a versatile option for use in many instances. This follow-on work explores further applications of the design, shares results and observations from prototyping efforts and discusses the logical next steps in the development of the current and derivative designs.

A novel curved beam compound flexure has been developed for alignment of multiple aspheric optics on a motorized rotation stage. This new flexure design combines design aspects of compound flexure stages with off-axis actuation to reduce size of the adjustment stage while maintaining relatively large travel range. The flexure design presented provides alignment for ten 12.7 mm diameter optics; each optic position’s flexure has an adjustment resolution of 0.6 microns and 1.0 mm of travel. This flexure design also includes built-in hard stops to minimize over-travel during adjustment, and engineered features to minimize tilt and rotation during adjustment. Design optimization of the flexure and finite element models are presented with design comparisons to previous eccentric adjuster designs.

The Advanced Photon Source Upgrade (APS-U) project will construct several new, best-in-class beamlines and enhancements to existing beamlines to exploit the massive increase in coherent flux enabled by the new storage ring lattice. APS-U will also enhance several existing beamlines to boost their performance. X-ray tomography is a common imaging mode for several of these beamlines, so there is demand for the highest-precision rotation of the sample. For example, the In Situ Nanoprobe (ISN, 19-ID), a next-generation hard x-ray nanoprobe, will use x-ray fluorescence tomography and ptychographic 3D imaging as key imaging modes with a spot size of 20 nm. It will require <100 nm runout and single-micro-radian wobble errors of the rotation stage to achieve full 3D resolution. Such precise requirements for a rotation stage can be achieved with air bearing rotation stages. However, this approach puts constraints on sample positioning design in terms of the sample environment (air bearing stages are generally not vacuum compatible) and the large mass of air bearing rotation stages. Mechanical bearing stages do not equal the precision runout/wobble specifications of air bearings. In order to use mechanical stages and approach air bearing level precision, the errors of the mechanical stage have to be measured precisely. We have then designed a metrology system using interferometer or capacitive sensors for the nanopositioning support lab as a diagnostic tool and to be portable for quality assurance testing of stages at the beamline.

The Off-plane Grating Rocket Experiment (OGRE) is a sounding rocket payload designed to obtain a high-resolution soft X-ray spectrum of Capella. OGRE’s optical system uses new technologies including state-of-the-art X-ray optics, custom arrays of reflection gratings, and an array of EM-CCDs. Many of these technologies will be tested for the first time in flight with OGRE. To achieve the high performance that these new technologies are capable of, the payload components must be properly aligned to meet high tolerances. This paper will outline OGRE’s opto-mechanical design for achieving alignment within these tolerances. Specifically, the design of the X-ray grating arrays will be discussed.

The ultimate design goal of an imaging optical system subjected to thermal and dynamic loads is to minimize system level wavefront error (WFE). System WFE is impossible to predict from finite element random response results due to the loss of phase information. In the past, the use of system WFE was limited by the difficulty of obtaining a linear optics model (LOM). In this paper, an automated method for determining system level WFE using a linear optics model is presented. The technique is applied to a simple telescope using structural optimization to automatically handle the conflicting design requirements of thermal and random response loads. The technique is demonstrated by example with SigFit, a commercially available tool integrating mechanical analysis with optical analysis.

Modern space system prototyping calls for bold, non-sequential approaches to engineering design. Embracing such an approach poses a new challenge on the design of passive vibration isolation systems: Accommodating large uncertainties in the payloads they support. Isolators are typically tuned and configured to the exact mass properties of the payload and do not perform well outside those assumptions. The number of candidate isolator configurations across which random vibration performance must be assessed also presents a significant challenge. This effort is observed to scale with 10^N, where N is the number of design variables studied. Here, 10^24 practical, unique designs were available. Our work describes the application of robust optimization techniques, global search algorithms, and massively parallelized job execution inside the LLIMAS software environment to overcome such computational challenges and identify isolator configurations that provide acceptable attenuation over a wide range of payload assumptions. Final geometry for the selected point design is presented, and performance comparisons of gradient-based, local, robust, non-robust and genetic algorithms are discussed.

Topology optimization is a design technique that evaluates and determines the optimal material distribution, within a domain, given an objective function and constraint. For the flat, round mirror in this report, the objective function is to obtain maximum stiffness while minimizing the mass. An optimized open-back Beryllium mirror will be evaluated for mass and structural properties. These results will be used to influence a topology optimization study of a closed-back (sandwich) mirror made from an Aluminum, Silicon, and Magnesium alloy, AlSi10Mg, with similar properties to Aluminum 6061. The AlSi10Mg alloy used for this study was chosen for the combination of mechanical properties and usage in additive manufacturing.

In conducting a STOP analysis, it is often required to convert laser fluence maps or voxel maps from an optical analysis into finite element heat loads for thermal and thermoelastic analyses. These fluence maps are usually represented as a rectangular array at optical surfaces. A technique has been developed to convert these maps into surface and volumetric loads on arbitrary 2D and 3D finite element (FE) meshes. For lenses, any number of intermediate maps through the lens thickness are allowed when more resolution is required. Another output format used by optics codes is three dimensional cubes called voxels. Voxel data can also be converted to FE loads. As data checks, the total heat absorbed is reported for each surface and each lens volume and compared to the FE load created. The technique is available in SigFit, a commercially available tool integrating mechanical analysis with optical analysis.

Using a compact laminar overconstrained flexure bending mechanism and a capacitive sensor array, a precision compact mirror bending mechanism for 300-mm long hard x-ray mirror has been designed and constructed to perform initial test for x-ray zoom optics as a part of an Argonne Laboratory-Directed Research and Development project at the Advanced Photon Source. A Finite Element Model (FEM) of the mirror bender was created with commercial simulation software. An iterative process of simulations were run to predict accurate bending parameters for the flexure bending mechanism.The FEM simulation demonstrated a result of an elliptically bent trapezoid mirror surface that fit with desired elliptical mirror profile within ±20 nanometers over 86% of the mirror’s measured length. The iteration process of model refinement, results of the finite element simulations, and preliminary test of the capacitive sensor array are discussed in this paper.

The performance, affordability and reliability of optical systems is dictated by following good systems engineering practices when defining the architecture, specifications and verification methods. Clearly written requirements document and associated verification documents have a direct positive impact on the development costs and schedule. These documents must convey not only the performance, environmental, reliability and lifetime requirements but also the associated processes and materials that can or cannot be used. All these requirements must be clearly spelled out while keeping the associated verification methods in mind. These well written documents enable the optical, mechanical, electrical and algorithm designers to understand how well the optical system needs to be designed to deliver its intended performance within the cost and schedule constraints. This paper describes the content that must be covered in a good requirements documents. Such a comprehensive requirements document is essential for producing sophisticated optical systems that are not only cost-effective but also deliver superior and reliable performance during their intended missions.

During qualification thermal testing of the Transiting Exoplanet Survey Satellite (TESS) lens assemblies, an anomalous focus change was observed during thermal-vacuum testing at its cold operating temperature (-75°C to - 85°C). Optical testing of the lens assemblies performed in the thermal-vacuum chamber indicated the magnitude and direction of the focus change, but did not identify the specific changes in the lens elements that were causing the focus shift. Individual lens motions measured using an interferometer indicated that lens vertices were moving relative to one another in a way that was inconsistent with predictions from detailed structural/thermal/optical (STOP) modeling. Further STOP analysis indicated the focus and vertex motion data were consistent with changes in lens curvature, suggesting that radial forces were deforming the lens. Finite element modeling showed that material property changes in the silicone adhesive material (room temperature vulcanizing, RTV 566) used to bond the lenses to the aluminum bezels could produce the necessary forces. The root cause of the focus shift was suspected to be unanticipated crystallization of the RTV 566 which has not previously been documented. Despite its widespread use, very little information has been published about the mechanical properties of RTV 566, and typical thermomechanical testing of its behavior has always utilized temperature sweeps. For this investigation, extensive testing was performed to characterize material property changes of RTV 566 samples under isothermal conditions at low temperatures (-75 to -85°C), for extended periods and at different levels of applied strain. The data presented here provide conclusive evidence that RTV 566 experiences time-dependent changes in mechanical properties that are consistent with crystallization phenomena.

The project “High loading precision rotation stage design for synchrotron radiation mirror measurement” aims to provide an ultra-high-precision heavy-duty rotation stage and X-ray mirror interference optical measurements. Since the shape of an X-ray lens is very different from that of the general visible optical lens, the measurement system is very different from the general visible light optical measurement system. This paper describes a high-load precision rotating platform for obtaining stitching interferometer measurements for a synchrotron radiation mirror. The synchrotron radiation mirror is usually rectangular, and the length is greater than the interferometer measurement size. Therefore, for the mirror measurement, the stitching method is usually used to obtain synchrotron radiation mirror measurements. The interference measurements are obtained at different positions. In order to obtain the measurements, the center line of the interferometer must be perpendicular to the tangent of the mirror surface, so that appropriate interference fringes can be obtained. As the mirror radius becomes smaller, the interferometer rotation angle sensitivity increases. Development of the stitching interferometer high-load precision rotating platform design target requires an angle rotation resolution <10 nrad, considering the weight of the general interferometer plus the reference lens, related accessories, and safety factors is about 50 kg so that the rotating platform design load is 70 kg.

We have used a simple digital still camera, instead of a conventional video-rate camera, to capture high-resolution images in a shearographic system. The high-resolution, compressed JPEG still images (of 18 megapixel resolution) are only generated by the camera on command from the controlling PC. We successfully generated shearograms from the still images, which are indicative of the applied stresses on the test object. The test object in this case is a center-loaded metal plate, fixed at the edges. The use of a digital still camera simplifies the electronic part of the shearographic system, and prevents the generation of unnecessary images. We propose to apply the system in several different applications.

Design and development of large SiC mirror has been conducted. By using the finite element analysis program NX NASTRAN we calculated the opto-mechanical performance of mirror and its support system under various design loads including gravity, temperature and dynamic loads. The optical performance has been analyzed by using Zernike polynomials based on corrected RMS surface error. We also optimized a bi-pod type flexure bonded at the backside of the mirror with proper strength under environment of space-borne application. The prototype SiC mirror has been generated with proper opto-mechanical strength and good optical performance. Detailed development process of manufacturing of the mirror with grinding, polishing, bonding and environment test will be discussed herein.

In missile applications, decision of optical design is critical for system performance. Many kind of optical solution can be chosen with respect to missile criteria. However, some kinds of limitation coming from system criteria eliminate some of optical design alternative. Also validation of optical design is another subject. Design results from simulation should satisfy reality. Some parameters such as modulation transfer function, noise equivalent temperature difference and field of view should be tested for optomechanical module performance. Also, module range performance capability with automatic target acquisition algorithm match with test results. Starting from the design phase to production results, all process should be tested. To achieve that simulation results from the programs are compared in laboratory environment. Finally laboratory results are compared with missile criteria.

Beam steering optical arrangement needs less volume envelope. However because of the optical path difference and other aberration factor, image will be disrupted. Performance of optical design will be affected from these kinds of aberrations. In missile applications, small dimension is important for aerodynamic effects. Using regular gimbal approach increase dimension, but using beam steering method in missile application instead of regular gimbal approach has beneficial in aerodynamically. However performance of system will be affected. Because of that reason two Risley prisms are produced and optical system design is tested at laboratory condition. Change of MTF is measured and its automatic target acquisition performance is measured with respect to Risley prisms’ position. Finally results are compared with theoretical results.

In missile applications, countermeasures are one of critical aspects to be handled. New technological improvements affect missile performance because of effectiveness of countermeasures. To eliminate countermeasures’ effects, different mode seeker will be need. Two or more different modes in seeker increase immunity to different kind of countermeasures. Because of these reasons, two different modes are chosen for seeker design of this work. One of them is millimeter wave and other one is four quadrant. By using this two different seeker concept, weakness of individual system will be eliminated by each other. In this work millimeter wave and four quadrant system range performance will be calculated and optomechanical design will be shown with respect to some sample missile criteria. After that seeker performance of system will be compared with other dual mode seekers.

In missile application, seeker performance is directly affected by stabilization performance of gimbal. Since missile high velocity, imaging part of seeker is affected from vibration profile. This vibration cause blurring in image part. To understand response of seeker, some theoretical gimbal modeling for a conceptual seeker is done. Also optomechanical design is finished and produced with respect to conceptual seeker. For different stabilization levels under vibration profile, performance of the automatic target acquisition algorithm performance is tested. Finally, laboratory results are compared with model results.