This PDF file contains the front matter associated with SPIE Proceedings Volume 10371, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

Fastening optical elements with adhesives presents challenges when dissimilar materials (almost always the case) are encountered and environmental exposures from temperature changes, shock and vibration must be met. A brief review of standard processes will be followed by a selection criteria for the optic, its substrate, the bond geometry, surface preparation, application and cure. Common analysis practices will be compared to Finite Element models. The impact of stress in terms of distortion and level of risk of bond failure is highlighted. Trade-offs will be presented as aids in determination of the best approach. Some areas addressed will be different adhesive types, matching CTE's, stress effects, athermal bonds, monolithic designs, and the use of flexures.

Adhesive mounting of lenses can allow flexible position control of each optical element, low stress, low part count, and precise alignment of lens assemblies in addition to high durability with respect to thermal expansion, shock, and vibration. Historic implementations of this method carried risk of UV degradation, photo contamination, long term stability, and long assembly cycle times. Others have developed non-adhesive friction/contact approaches to mount lenses but with significant compromises in durability and product cost. These two methods are compared and an optimal approach to achieve high lens mounting durability, low cycle time and negligible photo-contamination is demonstrated. Durability of this adhesive mounting solution will be established with examples including shock and vibration, mechanical stress decoupling factors, and optical stability over a wide range of shipping temperatures.

Increased demand for using the glass ceramic ZERODUR® with high mechanical loads called for strength data based on larger statistical samples. Design calculations for failure probability target value below 1: 100 000 cannot be made reliable with parameters derived from 20 specimen samples. The data now available for a variety of surface conditions, ground with different grain sizes and acid etched for full micro crack removal, allow stresses by factors four to ten times higher than before. The large sample revealed that breakage stresses of ground surfaces follow the three parameter Weibull distribution instead of the two parameter version. This is more reasonable considering that the micro cracks of such surfaces have a maximum depth which is reflected in the existence of a threshold breakage stress below which breakage probability is zero. This minimum strength allows calculating minimum lifetimes. Fatigue under load can be taken into account by using the stress corrosion coefficient for the actual environmental humidity. For fully etched surfaces Weibull statistics fails. The precondition of the Weibull distribution, the existence of one unique failure mechanism, is not given anymore. ZERODUR® with fully etched surfaces free from damages introduced after etching endures easily 100 MPa tensile stress. The possibility to use ZERODUR® for combined high precision and high stress application was confirmed by the successful launch and continuing operation of LISA Pathfinder the precursor experiment for the gravitational wave antenna satellite array eLISA.

The development of novel Al-, Ge- doped and un-doped standard single mode fibers for future optical communication at 2μm requires the integration of, among other pieces of equipment, an optical time domain reflectometry (OTDR) technique for precise spectral attenuation characterization, including the well-known cut-back method. The integration of a state of the art OTDR at 2μm could provide valuable attenuation information from the aforementioned novel fibers. The proposed setup consists of a 1.7 mW, 1960nm pump source, a 30 dB gain Thulium doped fibre amplifier at 2μm, an 0.8mm focal length lens with a 0.5 NA, a 30 MHz acusto-optic modulator, a 3.1 focal length lens with a 0.68NA, an optical circulator at 2μm, an InGaAs photodetector for 1.2 nm-2.6 nm range, a voltage amplifier and an oscilloscope. The propagated pulse rate is 50 KHz, with 500 ns, 200 ns, 100 ns and 50 ns pulse widths. Attenuation versus novel fibers types for lengths ranging from 400- to 1000- meter samples were obtained using the proposed setup.

MIT Lincoln Laboratory’s Integrated Modeling and Analysis Software (LLIMAS) enables the development of novel engineering solutions for advanced prototype systems through unique insights into engineering performance and interdisciplinary behavior to meet challenging size, weight, power, environmental, and performance requirements. LLIMAS is a multidisciplinary design optimization tool that wraps numerical optimization algorithms around an integrated framework of structural, thermal, optical, stray light, and computational fluid dynamics analysis capabilities. LLIMAS software is highly extensible and has developed organically across a variety of technologies including laser communications, directed energy, photometric detectors, chemical sensing, laser radar, and imaging systems. The custom software architecture leverages the capabilities of existing industry standard commercial software and supports the incorporation of internally developed tools. Recent advances in LLIMAS’s Structural-Thermal-Optical Performance (STOP), aeromechanical, and aero-optical capabilities as applied to Lincoln prototypes are presented.

The author’s previous work describes the simple diffraction grating in which the plane of incidence at the grating’s substrate is orthogonal to the lay of the grating. This work develops the equations for the general case where the lay of the grating is rotated with respect to its surface normal so the direction of the desired diffraction order is a compound angle in the grating’s coordinate system. The optomechanical constraint equations are developed and an example of their application is shown.

Thermally induced stress is readily calculated for linear elastic material properties using Hooke’s law in which, for situations where expansion is constrained, stress is proportional to the product of the material elastic modulus and its thermal strain. When material behavior is nonlinear, one needs to make use of nonlinear theory. However, we can avoid that complexity in some situations. For situations in which both elastic modulus and coefficient of thermal expansion vary with temperature, solutions can be formulated using secant properties. A theoretical approach is thus presented to calculate stresses for nonlinear, neo-Hookean, materials. This is important for high acuity optical systems undergoing large temperature extremes.

Affordability and reliability are equally important as the performance and development time for many optical systems for military, space and commercial applications. These characteristics are even more important for the systems meant for space and military applications where total lifecycle costs must be affordable. Most customers are looking for high performance optical systems that are not only affordable but are designed with “no doubt” mission assurance, reliability and maintainability in mind. Both US military and commercial customers are now demanding an optimum balance between performance, reliability and affordability. Therefore, it is important to employ a disciplined systems design approach for meeting the performance, cost and schedule targets while keeping affordability and reliability in mind. The US Missile Defense Agency (MDA) now requires all of their systems to be engineered, tested and produced according to the Mission Assurance Provisions (MAP). These provisions or requirements are meant to ensure complex and expensive military systems are designed, integrated, tested and produced with the reliability and total lifecycle costs in mind. This paper describes a system design approach based on the MAP document for developing sophisticated optical systems that are not only cost-effective but also deliver superior and reliable performance during their intended missions.

The Habitable Exoplanet Imaging Mission (HabEx) is a NASA flagship mission to be considered for the 2020 Decadal Survey in Astronomy and Astrophysics. The concept is to develop an imaging system to detail the characteristics of planetary systems surrounding solar-type stars. The system must provide high contrast imaging and spectroscopy with a high signal-to-noise ratio and high stability. In this paper, we will present a point design for a 4 meter, off-axis, monolithic primary mirror to be used in the HabEx imaging system. An initial optimization of design parameters was performed to minimize distortions due to vibration while also maintaining a low areal density. Finite Element Models (FEM) of mirrors were created with varying mounting configurations, materials, depths, rib thicknesses, cell sizes, facesheet thicknesses, and depths. A harmonic analysis was performed on each model, and the corresponding displacements were output from the optical surface. The data from each model was imported into MATLAB and the distortion on the optical surface of each model was analyzed. Thus, the optimal design parameters were chosen based on the vibration performance of each design. The analysis and the chosen point design will be discussed further throughout the paper.

The ever-increasing spatial resolution of nanofocusing hard x-ray optics, coupled with the need for long working distances and spectroscopic imaging, requires stages that translate optics and samples over millimeters with trajectory errors of under 10 nm. To overcome the performance limitations of precision ball-bearing-based or roller-bearing-based linear stage systems, compact vertical and horizontal linear nanopositioning flexure stages, with centimeter-level travel range, have been designed and tested at the Advanced Photon Source (APS) for x-ray instrumentation applications. The mechanical design and finite element analyses of the flexural stages, as well as its preliminary test results with laser interferometers are described in this paper.

With the current drive towards diffraction limited storage rings, hard x-ray optics will require subsequent increases in positioning accuracy over large travel ranges. Nanometer-level precision positioning requires the use of compliant mechanisms to remove friction and backlash type errors. Ideally, the compliant mechanism is compliant in the direction of desired travel and rigid in all other directions. However, in reality, there is still compliance in these other directions, particularly for flexure pivots, which lead to parasitic trajectory errors. In this paper we analyze the trajectory errors of a linear guiding mechanism, composed of commercially available C-Flex Bearing Co. Inc. and Riverhawk Co. flexure pivots, using finite element analysis and experimental measurements. The guide is designed as an assembly of double parallel 4-bar type deformation compensated linear guiding mechanisms, and incorporates a novel 1:2 stabilizer unit to control the middle-bar. The focus of the analysis is on the trajectory errors caused by rotation center shift, manufacturing tolerances, flexure pivot size, assembly tolerances, and includes a discussion of methods to mitigate these errors.

In general, the drop-in and cell-mounted assembly are used for standard and high performance optical system respectively. The optical performance is limited by the residual centration error and position accuracy of the conventional assembly. Recently, the poker chip assembly with high precision lens barrels that can overcome the limitation of conventional assembly is widely applied to ultra-high performance optical system. ITRC also develops the poker chip assembly solution for high numerical aperture objective lenses and lithography projection lenses. In order to achieve high precision lens cell for poker chip assembly, an alignment turning system (ATS) is developed. The ATS includes measurement, alignment and turning modules. The measurement module including a non-contact displacement sensor and an autocollimator can measure centration errors of the top and the bottom surface of a lens respectively. The alignment module comprising tilt and translation stages can align the optical axis of the lens to the rotating axis of the vertical lathe. The key specifications of the ATS are maximum lens diameter, 400mm, and radial and axial runout of the rotary table < 2 μm. The cutting performances of the ATS are surface roughness Ra < 1 μm, flatness < 2 μm, and parallelism < 5 μm. After measurement, alignment and turning processes on our ATS, the centration error of a lens cell with 200mm in diameter can be controlled in 10 arcsec. This paper also presents the thermal expansion of the hydrostatic rotating table. A poker chip assembly lens cell with three sub-cells is accomplished with average transmission centration error in 12.45 arcsec by fresh technicians. The results show that ATS can achieve high assembly efficiency for precision optical systems.

The refraction lithography lens has many units, which are easily deformed by gravity forces. However, the lens mount flexure design can relieve lens surface gravity deformation. The lithography lens generically has more than 10 lens units, so with each unit, the gravity deformation sum will create large aberrations in the system. The flexure number can generate a relative aberration, such as trefoil, tetrafoil, and high-order aberrations. In addition, the lens flexure orientation can compensate for non-symmetric to symmetric aberrations from effects of gravity deformation. Thus, symmetric aberrations must resist magnitude in one or two lens units through the measurement data. This study attempts to calculate and predict lens gravity deformation; the results can assist with optical design and reoptimize system performance, as well as reduce the rework risk by measurement data.

The Double Arm Linkage precision Linear motion (DALL) carriage has been developed as a simplified, rugged, high performance linear motion stage. Initially conceived as a moving mirror stage for the moving mirror of a Fourier Transform Spectrometer (FTS), it is applicable to any system requiring high performance linear motion. It is based on rigid double arm linkages connecting a base to a moving carriage through flexures. It is a monolithic design. The system is fabricated from one piece of material including the flexural elements, using high precision machining. The monolithic design has many advantages. There are no joints to slip or creep and there are no CTE (coefficient of thermal expansion) issues. This provides a stable, robust design, both mechanically and thermally and is expected to provide a wide operating temperature range, including cryogenic temperatures, and high tolerance to vibration and shock. Furthermore, it provides simplicity and ease of implementation, as there is no assembly or alignment of the mechanism. It comes out of the machining operation aligned and there are no adjustments. A prototype has been fabricated and tested, showing superb shear performance and very promising tilt performance. This makes it applicable to both corner cube and flat mirror FTS systems respectively.

The ultimate goal of an active mirror system is to control system level wavefront error (WFE). In the past, the use of this technique was limited by the difficulty of obtaining a linear optics model. In this paper, an automated method for controlling system level WFE using a linear optics model is presented. An error estimate is included in the analysis output for both surface error disturbance fitting and actuator influence function fitting. To control adaptive optics, the technique has been extended to write system WFE in state space matrix form. The technique is demonstrated by example with SigFit, a commercially available tool integrating mechanical analysis with optical analysis.

The ultimate design goal of an optical system subjected to dynamic loads is to minimize system level wavefront error (WFE). In random response analysis, system WFE is difficult to predict from finite element results due to the loss of phase information. In the past, the use of ystem WFE was limited by the difficulty of obtaining a linear optics model. In this paper, an automated method for determining system level WFE using a linear optics model is presented. An error estimate is included in the analysis output based on fitting errors of mode shapes. The technique is demonstrated by example with SigFit, a commercially available tool integrating mechanical analysis with optical analysis.

The Transiting Exoplanet Survey Satellite (TESS) is an instrument consisting of four, wide fieldof- view CCD cameras dedicated to the discovery of exoplanets around the brightest stars, and understanding the diversity of planets and planetary systems in our galaxy. Each camera utilizes a seven-element lens assembly with low-power and low-noise CCD electronics. Advanced multivariable optimization and numerical simulation capabilities accommodating arbitrarily complex objective functions have been added to the internally developed Lincoln Laboratory Integrated Modeling and Analysis Software (LLIMAS) and used to assess system performance. Various optical phenomena are accounted for in these analyses including full dn/dT spatial distributions in lenses and charge diffusion in the CCD electronics. These capabilities are utilized to design CCD shims for thermal vacuum chamber testing and flight, and verify comparable performance in both environments across a range of wavelengths, field points and temperature distributions. Additionally, optimizations and simulations are used for model correlation and robustness optimizations.

This paper puts forward an adaptive optics (AO) mounting method of large aperture KDP frequency doubler used in high power solid state lasers. Integrated optomechanical theory is proposed and applied to verify the mechanical and optical performances of this AO method particularly. According to the thin plate theory and nonlinear optics theory, optomechanical model is developed. Then, the finite element method is employed to establish the numerical model and simulate the distortion process of the crystal plates under various boundary conditions. The results indicate that this AO method could correct the deformed surface and modify the phase matching condition significantly, which means the second harmonic generation (SHG) efficiency will be improved as well.

Mounting large reflective-refractive optical elements for cryogenic space application requires careful engineering. Optical wavefront error performance is balanced with surviving launch environments and cryogenic temperatures. Mounting and ground testing of a 25 cm by 15 cm plano germanium optical beamsplitter element was completed. Cryogenic WFE testing was performed down to 115 K predicting compliance to operational environment performance requirements. This paper discusses the mount engineering including detailed analysis, testing, and results.

The adaptive optics system for the Thirty Meter Telescope (TMT) is the Narrow-Field InfraRed Adaptive Optics System (NFIRAOS). Recently, INO has been involved in the optomechanical design of several subsystems of NFIRAOS, including the Instrument Selection Mirror (ISM), the NFIRAOS Beamsplitters (NBS), and the NFIRAOS Source Simulator system (NSS) comprising the Focal Plane Mask (FPM), the Laser Guide Star (LGS) sources, and the Natural Guide Star (NGS) sources. This paper presents an overview of these subsystems and the optomechanical design approaches used to meet the optical performance requirements under environmental constraints.

Lockheed Martin Space Systems Company Optical Payloads Center of Excellence is in process of standing up the Robotic Optical Assembly System (ROAS) capability at Lockheed Martin Coherent Technologies in Colorado. This currently implemented Robotic Optical Assembly has enabled Lockheed Martin to create world-leading, ultra-lowSWAP photonic devices using a closed-loop control robot to precisely position and align micro-optics with a potential fill factor of >25 optics per square inch. This paper will discuss the anticipated applications and optical capability when ROAS is fully operational, as well as challenge the audience to update their "rules of thumb" and best practices when designing low-SWAP optical-mechanical systems that take advantage of Lockheed Martin's ROAS capability. This paper will reveal demonstrated optical pointing and stability performance achievable with ROAS and why we believe these optical specifications are relevant for the majority of anticipated applications. After a high level overview of the ROAS current state, this paper will focus in on recent results of the "Reworkable Micro-Optics Mounting IRAD". Results from this IRAD will correlate to the anticipated optical specifications required for relevant applications.

The design process for an opto-mechanical sub-system is discussed from requirements development through test. The process begins with a proper mission understanding and the development of requirements for the system. Preliminary design activities are then discussed with iterative analysis and design work being shared between the design, thermal, and structural engineering personnel. Readiness for preliminary review and the path to a final design review are considered. The value of prototyping and risk mitigation testing is examined with a focus on when it makes sense to execute a prototype test program. System level margin is discussed in general terms, and the practice of trading margin in one area of performance to meet another area is reviewed. Requirements verification and validation is briefly considered. Testing and its relationship to requirements verification concludes the design process.

The goal of this paper is to study in which extent the use of Zemax is suited for athermalization purposes. The research questions targeted in this paper are: what are the differences in the formulation of materials’ thermal expansion between Zemax and Ansys; what is the impact on optical quality between both approaches; quantification of the differences between the two methodologies in terms of back focal length, spot radius and modulation transfer function (MTF). To quantify the differences between both approaches, it is used an objective working between -40°C and 110°C. Initially, only Zemax was used to evaluate the objective. Zemax considers a linear geometric expansion of every optical surface, which is here proved to not be the best approach to find a deformed geometry after a thermal load. The second approach is to create a 3D model and perform a finite element simulation in Ansys software. The input data is the thermal variation and the output is the deformed geometry of the lenses. Using SigFit software, it was possible to generate new mathematical equations of the deformed lenses and import this data into Zemax to start a new ray tracing. The new shape and location of lenses differs for both scenarios, and the difference in the focal plane shift is around 12%. The maximum spot radius difference is 27% and MTF relative error goes up to 16%. Zemax as a standalone software is valid if used as an initial guess for the optical designer. However, as a final stage for validation and detailed design, the approach containing Ansys and SigFit should be preferable.

In 2015, NSPO (National Space Organization) began to develop the sub-meter resolution optical remote sensing instrument of the next generation optical remote sensing satellite which follow-on to FORMOSAT-5. Upgraded from the Ritchey–Chrétien Cassegrain telescope optical system of FORMOSAT-5, the experimental optical system of the advanced optical remote sensing instrument was enhanced to an off-axis Korsch telescope optical system which consists of five mirrors. It contains: (1) M1: 550mm diameter aperture primary mirror, (2) M2: secondary mirror, (3) M3: off-axis tertiary mirror, (4) FM1 and FM2: two folding flat mirrors, for purpose of limiting the overall volume, reducing the mass, and providing a long focal length and excellent optical performance. By the end of 2015, we implemented several important techniques including optical system design, opto-mechanical design, FEM and multi-physics analysis and optimization system in order to do a preliminary study and begin to develop and design these large-size lightweight aspheric mirrors and flat mirrors. The lightweight mirror design and opto-mechanical interface design were completed in August 2016. We then manufactured and polished these experimental model mirrors in Taiwan; all five mirrors ware completed as spherical surfaces by the end of 2016. Aspheric figuring, assembling tests and optical alignment verification of these mirrors will be done with a Korsch telescope experimental structure model in 2018.

This article presents the opto-mechanical design of a primary mirror assembly of a ground-based telescope with optimization algorithm. The prototype of ground-based telescope – GSO RC16 with 16 inches diameter blank primary mirror had been manufactured in 2016. However, a telescope with a blank primary mirror is too heavy to carry on for the stargazer. Besides, deformations caused by temperature difference and gravity will do significant effect to the large aperture mirrors with high optical performance requirements. In order to reduce the weight and maintain the stiffness simultaneously, the lightweight design and mounting interface design are critical and important. There are four types of system architectures in this project, including (1) two types of lightweight mirror designs - honeycomb type segments and sector type segments; (2) two types of mounting interface designs - retainer type support and CFRP type support. The optimization results showed that (1) the lightweight ratio of the primary mirrors are greater than 70%; and (2) the PV value of the mirrors supported by optimal mounting interfaces with gravity effect as a tilt of about 45 degrees and ±20°C temperature difference effectively less than 1/4 λ.

An integrated optimum athermalization design and analysis system will be developed in the study. The distance between the primary and secondary mirrors for a remote sensing instrument (RSI) will be taken as the objective function to improve the influence of the environment temperature variation on the optical images. Under a developing RSI model, the athermalization design to the secondary mirror based on the established system integrating a computer-aided design software, materials library construction, finite element analysis and optimization program will be executed. The design variables of the barrel, supporting structure and shims will be carried under low temperature change requirement. The displacements of the secondary mirror with respect to primary mirror with the optimum athermalization design can be reduced to almost zero from -95.6 μm for low temperature thermal boundary conditions.

A magneto-rheological finishing (MRF) process for the post-treatment of diamond turning is presented to remove the periodic micro structures and sub-surface damages with improvement of the original figure and surface roughness. An off-axis aspherical mirror with electro-less nickel-phosphorus plated surface was machined by a Single point diamond turning machine (SPDTM) and MRF polisher. The machined surfaces were examined by a scanning low-coherence interferometer, and the technique of Fast Fourier Transformation (FFT) and Power Spectrum Density (PSD) were introduced to evaluate the residual diamond turning marks on the turned and polished surfaces. The turning marks, which was clearly visible on the diamond turned surface, were absolutely removed after MR process, and the surface roughness of the machined surface was improved from 6 nm(Sa) and 7 nm (Sq) to 2 nm(Sa) and 3 nm (Sq). Consequently, the experimental results indicate that MRF is suitable for removing periodic micro-patterns caused by diamond turning process with the progress of the original figure and surface roughness.

Based on the study of the current technology of MCP electron rinse and parameters testing, a new electron rinse and testing system with four working stations for large area MCP is developed. In this system, electron rinse for various large area MCP of diameter less than 100mm can be conducted on each station at the same time, and parameters could be tested at one of the stations in the process of the electron rinse at different stages. Four stations in the vacuum system can be converted to each other quickly and accurately by operating the mechanical transmission structure designed. The system's superior performance was shown by a series of tests and data.