This PDF file contains the front matter associated with SPIE Proceedings Volume 8125, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

Sticker shock for optomechanical hardware designed for advanced optical DEMVAL systems can lead to program loss. In optomechanical design it is important to manage this risk through easily manufacturable and inexpensive hardware to meet demands of lower budget programs. The optical and optomechanical design teams must work closely to optimize system design for ease of manufacture, and assembly, while at the same time minimizing the impacts to system performance. Effective teaming often results in unique/creative design solutions which enable future system development. Outlined are some novel optomechanical structure concepts, with 5 degrees of freedom (DOF), used to design a low cost DEMVAL optical system. The concepts discussed include inexpensive repeatable magnetic kinematic mounts, flexure rings for lens preloading, simplistic drop-in lens housing designs, and adjustable tooling ball metering rods which accommodate alignment in 5 DOF.

One of the critical elements in the Four Laser Guide Star Facility (4LGSF) for the ESO Very Large Telescope (VLT) is the Optical Tube Assembly (OTA), consisting of a stable 20x laser beam expander and an active tip/tilt mirror, the Field Selector Mechanism (FSM). This paper describes the design and performance testing of the FSM. The driving requirement for the FSM is its large stroke of ±6.1 mrad, in combination with less than 1.5 μrad RMS absolute accuracy. The FSM design consists of a Zerodur mirror, bonded to a membrane spring and strut combination to allow only tip and tilt. Two spindle drives actuate the mirror, using a stiffness based transmission to increase resolution. Absolute accuracy is achieved with two differential inductive sensor pairs. A prototype of the FSM is realized to optimize the control configuration and measure its performance. Friction in the spindle drive is overcome by creating a local velocity control loop between the spindle drives and the shaft encoders. Accuracy is achieved by using a cascaded low bandwidth control loop with feedback from the inductive sensors. The pointing jitter and settling time of the FSM are measured with an autocollimator. The system performance meets the strict requirements, and is ready to be implemented in the first OTA.

We report on the development of the fibre slit for the High Efficiency and Resolution Multi Element Spectrograph (HERMES). This paper discusses the design, mounting and alignment techniques of 784 science fibres and the magnificatin optics divided among two slit bodies. The measured performance of the fiber bundle shows an increased throughput of 50% in the existing AAOmega spectrograph using the same fiber mounting techniques.

The Giant Magellan Telescope (GMT) will be a 25m class telescope which is one of the extremely large telescope projects in the design and development phase. The GMT will have two Gregorian secondary mirrors, an adaptive secondary mirror (ASM) and a fast-steering secondary mirror (FSM). Both secondary mirrors are 3.2 m in diameter and built as seven 1.1 m diameter circular segments conjugated 1:1 to the seven 8.4m segments of the primary. The FSM has a tip-tilt feature to compensate image motions from the telescope structure jitters and the wind buffeting. The support system of the lightweight mirror consists of three axial actuators, one lateral support at the center, and a vacuum system. A parametric study and optimization of the FSM mirror blank and central lateral flexure design were performed. This paper reports the results of the trade study. The optical image qualities and structure functions for the axial and lateral gravity print-through cases, thermal gradient effects, and dynamic performances will be discussed for the case of a lightweighted segment with a center thickness of 140 mm weighing approximately 105 kg.

The University of Rochester is well known for the Institute of Optics as well as a strong Mechanical Engineering program. In recent years, there has been collaboration between the two departments on a variety of topics, including a new joint faculty position. There are new cross-listed courses in Optomechanics and Precision Engineering (Spring 2012), which are described in this paper. As yet, there is no formal specialization in Optomechanics, but many students create their own program from available courses combining optics and mechanics with other disciplines. Students have the opportunity to participate in the several research areas which cross discipline boundaries. For example, a student design team is building a 16" telescope which they hope can become the basis of an intercollegiate design contest. In addition to full semester courses, there is a summer program of short courses available to working engineers as both refresher courses or as introductory courses on new topics.

A prototype of a novel ultrahigh-resolution inelastic x-ray scattering spectrometer has been designed and tested at undulator-based beamline 30-ID, at the Advanced Photon Source (APS), Argonne National Laboratory. This state-of-the-art instrument is designed to meet challenging mechanical and optical specifications for producing ultrahigh-resolution inelastic x-ray scattering spectroscopy data for various scientific applications. The optomechanical design of the ultrahigh-resolution monochromator and analyzer for inelastic x-ray scattering spectrometer as well as the preliminary test results of its precision positioning performance are presented in this paper.

High-precision opto-mechanical structures have historically been plagued by high costs for both hardware and the associated alignment and assembly process. This problem is especially true for space applications where only a few production units are produced. A methodology for optical alignment and optical structure design is presented which shifts the mechanism of maintaining precision from tightly toleranced, machined flight hardware to reusable, modular tooling. Using the proposed methodology, optical alignment error sources are reduced by the direct alignment of optics through their surface retroreflections (pips) as seen through a theodolite. Optical alignment adjustments are actualized through motorized, sub-micron precision actuators in 5 degrees of freedom. Optical structure hardware costs are reduced through the use of simple shapes (tubes, plates) and repeated components. This approach produces significantly cheaper hardware and more efficient assembly without sacrificing alignment precision or optical structure stability. The design, alignment plan and assembly of a 4" aperture, carbon fiber composite, Schmidt-Cassegrain concept telescope is presented.

The Haystack radio telescope is being upgraded to support imaging radar applications at 96 GHz. The Cassegrain antenna includes a 37 m diameter primary reflector comprising 432 reflector panels and a 2.84 m diameter hexapod mounted subreflector. Top-level antenna performance is based on meeting diffraction-limited performance over an elevation range of 10 - 40° resulting in a maximum RF half pathlength error requirement of 100 μm RMS. RF-mechanical performance analyses were conducted that allocated subsystem requirements for fabrication, alignment, and environmental effects. Key contributors to system level performance are discussed. The environmental allocations include the effects of gravity, thermal gradients, and diurnal thermal variations which are the dominant error source. Finite element methods and integrated optomechanical models were employed to estimate the environmental performance of the antenna and provide insight into thermal management strategies and subreflector compensation. Fabrication and alignment errors include the manufacturing of the reflector surface panels and assembly of overall reflector surface.

Mechanical tolerances within an optical system can consist of a wide array of variables including machining tolerances, variability in material properties, uncertainty in applied loads, and discrete resolution of actuation hardware. This paper discusses methods to use integrated modeling and Monte Carlo techniques to determine the effect of such tolerances on optical performance so that the allocation of such tolerances is based upon optical performance metrics. With many random variables involved, statistical approaches provide a useful means to study performance metrics. Examples include the effect of mount flatness on surface RMS and Zernike coefficients and the effect of actuator resolution on the performance of an adaptively corrected deformable mirror. Coefficient of thermal expansion and thermal control tolerances impacting both line-of-sight errors and surface RMS errors are also addressed.

The Navy Prototype Optical Interferometer (NPOI), located near Flagstaff, Arizona, is a ground-based interferometer that collects and transports stellar radiation from six primary flat collectors, known as siderostats, through a common vacuum relay system to a beam combiner where the beams are combined, fringes are obtained and modulated, and data are recorded for further analysis. The current number of observable stellar objects can increase from 6,000 to approximately 47,000 with the addition of down-tilting beam compressors in the optical train. The increase in photon collection area from the beam compressors opens the sky to many additional and fainter stars. The siderostats are capable of redirecting 35 cm stellar beams into the vacuum relay system. Sans beam compressors, any portion of the beam greater than the capacity of the vacuum transport system, 12.5 cm, is wasted. Engineering analysis of previously procured as-built beam compressor optics show the maximum allowable primary mirror surface sag, resulting in λ/10 peak-to-valley wavefront aberration, occurs at 2.8° down-tilt angle. At the NPOI operational down-tilt angle of 20° the wavefront aberration reduces to an unacceptable λ/4. A design modification concept that reduces tilt-induced sag was investigated. Four outwardly applied 4-lb forces on the rear surface of the mirror reduce the sag from 155 nm to 32 nm at 20° down-tilt and reduce peak-to-valley wavefront deviation to λ/8.6. This preliminary effort indicates that this solution path is a viable and economic way to repair an expensive set of optical components. However, it requires further work to optimize the locations, magnitudes, and quantity of the forces within this system and their influence on the mirror surface.

A non-invasive self-measurement method for analyzing vibrations within a biological imaging system is presented. This method utilizes the system's imaging sensor, digital image processing and a custom dot matrix calibration target for in-situ vibration measurements. By taking a series of images of the target within a fixed field of view and time interval, averaging the dot profiles in each image, the in-plane coherent spacing of each dot can be identified in both the horizontal and vertical directions. The incoherent movement in the pattern spacing caused by vibration is then resolved from each image. Accounting for the CMOS imager rolling shutter, vibrations are then measured with different sampling times for intra-frame and inter-frame, the former provides the frame time and the later the image sampling time. The power spectrum density (PSD) analysis is then performed using both measurements to provide the incoherent system displacements and identify potential vibration sources. The PSD plots provide descriptive statistics of the displacement distribution due to random vibration contents. This approach has been successful in identifying vibration sources and measuring vibration geometric moments in imaging systems.

In optical lens assembly, metal retaining rings are often used to hold the lens in place. If we mount a lens to a sharp metal edge using normal retention force, high compressive stress is loaded to the interface and the calculated tensile stress near the contact area from Hertzian contact appears higher than allowable. Therefore, conservative designs are used to ensure that glass will not fracture during assembly and operation. We demonstrate glass survival with very high levels of stress. This paper analyzes the high contact stress between glass lenses and metal mounts using finite element model and to predict its effect on the glass strength with experimental data. We show that even though contact damage may occur under high surface tensile stress, the stress region is shallow compared to the existing flaw depth. So that glass strength will not be degraded and the component can survive subsequent applied stresses.

Lenses are typically mounted into precision machined barrels and constrained with spacers and retaining rings. The details of the interfaces between the metal and the glass are chosen to balance the accuracy of centration and axial position, stress in the glass, and the cost for production. This paper presents a systematic study of sharp edge, toroidal, and conical interfaces and shows how to control accuracy, estimate stress, and limit production costs. Results are presented from computer models, finite element simulations, and experimental testing.

For the Euclid mission a pre-development phase is implemented to prove feasibility of individual components of the system. The optical system of EUCLID Near-Infrared Spectrometer & Photometer (NISP) is composed of 4 lenses, bandpass filters and grisms. The lenses are made of different materials: the corrector lens (fused silica) directly behind the dichroic and the lenses L1 (CaF2), L2 (LF5G15), and L3 (LF5G15) that are mounted in a separate lens barrel design. Each lens has its separate mechanical interface to the lens barrel, the so called adaption ring. The adaption ring shall provide the necessary elasticity caused by different CTEs of the lens and ring materials, as well as shall allow the high position accuracy of the lenses relative to the lens barrel and the optical axis. The design drivers for the adaption ring are high precision, cryogenic operation temperature (150 K) and the large dimension of the lenses (150 - 170 mm). The design concept of the adaption ring is based on solid state springs, which shall both provide sufficient protection against vibration loads at ambient temperature as well as high precision (< ±10 μm) and stability at cryogenic temperatures. Criteria for the solid state spring design shall be low radial forces at cryogenic conditions to avoid any refractive index and polarization variations. The design shall be compliant to the large temperature differences between assembly and operation, the high precision and non-deformation requirements of the lenses as well as to the deviating CTEs of the selected lens materials. The paper describes the selected development approach including justification, thermal and structural analysis.

Since future astrophysics missions require space telescopes with apertures of at least 10 meters, there is a need for on-orbit assembly methods that decouple the size of the primary mirror from the choice of launch vehicle. One option is to connect the segments edgewise using mechanisms analogous to damped springs. To evaluate the feasibility of this approach, a parametric ANSYS model that calculates the mode shapes, natural frequencies, and disturbance response of such a mirror, as well as of the equivalent monolithic mirror, has been developed. This model constructs a mirror using rings of hexagonal segments that are either connected continuously along the edges (to form a monolith) or at discrete locations corresponding to the mechanism locations (to form a segmented mirror). As an example, this paper presents the case of a mirror whose segments are connected edgewise by mechanisms analogous to a set of four collocated single-degree- of-freedom damped springs. The results of a set of parameter studies suggest that such mechanisms can be used to create a 15-m segmented mirror that behaves similarly to a monolith, although fully predicting the segmented mirror performance would require incorporating measured mechanism properties into the model.

An analytical tool is presented which supports the opto-mechanical design of bonded optical elements. Given the mounting requirements from the optical engineer, the alignment stability and optical stresses in bonded optics can be optimized for the adhesive and housing material properties. While a perfectly athermalized mount is desirable, it is not realistic. The tool permits evaluation of element stability and stress over the expected thermal range at nominal, or worst case, achievable assembly and manufacturing tolerances. Selection of the most appropriate mount configuration and materials, which maintain the optical engineer's design, is then possible. The tool is based on a stress-strain analysis using Hooke's Law in the worst case plane through the optic centerline. The optimal bond line is determined for the selected adhesive, housing and given optic materials using the basic athermalization equation. Since a mounting solution is expected to be driven close to an athermalized design, the stress variations are considered linearly related to strain. A review of the equation set, the tool input and output capabilities and formats and an example will be discussed.

The Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) is an innovative design for a wide-field imaging facility developed at the University of Hawaii's Institute for Astronomy. The Pan-STARRS prototype telescope (PS1) is an Altitude over Azimuth telescope with an instrument rotator for its 1.4gigapixel camera. Quartus Engineering Incorporated (Quartus) performed modal survey and operational vibration testing of the Pan-STARRS prototype telescope (PS1) to assess the impact of structural resonance and star tracking (i.e. actuated telescope motion) on image quality. The telescope's modal parameters: resonant frequencies, modes shapes, and damping ratios; were measured using an impact hammer and the acceleration response gathered from components with natural modes of vibration identified in a pre-test structural analysis that that were thought to affect image quality. A baseline characterization of the PS1's elastic performance was performed and compared with real-time structural modifications to determine how an individual component's stiffness affects the telescope's overall elastic performance. Operational vibration data collected at various on-sky tracking states was then evaluated using the newly measured modal properties and legacy optical measurements to develop a relationship between elastic motion and image quality.

Representative failure data for structural epoxies can be very difficult to find for the optomechanical engineer. Usually, test data is only available for shear configuration at room temperature and fast pull rate. On the other hand, the slowly induced stress at extreme temperature is for many optical systems the worse-case scenario. Since one of the most referenced epoxy for optical assembly is the 3M™ Scotch-Weld™ Epoxy Adhesive EC-2216 B/A Gray, better understanding its behavior can benefit a broad range of applications. The objective of this paper is two-fold. First, review data for critical parameters such as Young's modulus and coefficient of thermal expansion. Secondly, derive failure criteria from correlation between a thermal stress experiment and a finite element model. Instead of pulling out a standard tensile specimen, it is proposed to test thin bondline geometry to replicate an optical device usage. Four test plates are assembled at the Institut National d'Optique (INO) in Quebec City, Canada with bondlines of 50 μm and 133 μm. To detect the failure of the epoxy, the low level vibration signature of a cantilever Invar plate is monitored as temperature changes. Following the finite element analysis, a failure criterion is found to better match the experimental results than generic lap shear data.

With the ever increasing desire for range and delivery capabilities of ballistic defence equipment, weapons and sight systems are constantly evolving in complexity. As a result current systems now incorporate more sophisticated technology than ever before. This paper describes the non-intrusive mechanical field data acquisition and subsequent analysis and test integration techniques performed on complex opto-mechanical weapon mounted systems. As a result of physical acquisition, innovative techniques have been developed to enable the synthesis of the transient recordings for the purpose of finite element analysis. Further investigations have revealed new possibilities in applying more accurately controlled 'in house' loads, for low cost representative test purposes.

This works describes a novel optical refraction index sensor which is based on the analysis of double reflection lecture detection. This process initially identifies the thickness of a semitransparent solid o liquid material by the retro-reflection of a laser diode at 633nm as a function of distance along the device under test with a Z-axis scanner to find the focusing point. This feedback signal brings how far traveled the beam path which is indirectly related with the refractive index at different materials, the data of the thickness at each layer is treating with a geometrical analysis of the beam velocity.

The Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) has an optical prescription which employs four triplet lens cells. The instrument will operate at 35K after experiencing launch loads at approximately 295K and the optic mounts must accommodate all associated thermal and mechanical stresses, plus maintain an exceptional wavefront during operation. Lockheed Martin Space Systems Company (LMSSC) was tasked to design and qualify the bonded cryogenic lens assemblies for room temperature launch, cryogenic operation, and thermal survival (25K) environments. The triplet lens cell designs incorporated coefficient of thermal expansion (CTE) matched bond pad-to-optic interfaces, in concert with flexures to minimize bond line stress and induced optical distortion. A companion finite element study determined the bonded system's sensitivity to bond line thickness, adhesive modulus, and adhesive CTE. The design team used those results to tailor the bond line parameters, minimizing stress transmitted into the optic. The challenge for the Margin of Safety (MOS) team was to design and execute a test that verified all bond pad/adhesive/ optic substrate combinations had the required safety factor to generate confidence in a very low probability optic bond failure during the warm launch and cryogenic survival conditions. Because the survival temperature was specified to be 25K, merely dropping the test temperature to verify margin was not possible. A shear/moment loading device was conceived that simultaneously loaded the test coupons at 25K to verify margin. This paper covers the design/fab/SEM measurement/thermal conditioning of the MOS test articles, the thermal/structural analysis, the test apparatus, and the test execution/results.

Most of the mirror mounting literature has focused on small (less than 0.1 meters) or large (greater than 1 meter) mirrors. We will examine the theory and practice of mounting moderately sized mirrors (between 0.1 and 1 meter). Two examples will be taken from optical diagnostic systems designed for the National Ignition Facility (NIF). In both cases the mirrors were removable (not bonded in place). One of the examples will be for a mirror with a poor aspect ratio (i.e. diameter to thickness ratio greater than 15:1).

We explain a new lens mounting scheme using cascaded ring flexures for minimizing thermal stresses. Two circular rings are concentric at the adhesive insertion hole and made monolithically on a lens cell. Six degree-of-freedom motions can be accommodated by controlling dimensional parameters. Thermo-elastic deformations are evaluated by interferometric measurements and are verified with finite element analyses. Athermal performances from a simple elastomeric mount and a ring-flexured mount are also compared. This lens mounting scheme was successfully applied to our space-borne optical system and will be a promising candidate for environmentally challenged optical systems such as military applications.

The Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) includes numerous optical assemblies. The instrument will operate at 35K after experiencing launch loads at ~293K and the optic mounts must accommodate all associated thermal and mechanical stresses, plus maintain exceptional optical quality during operation. Lockheed Martin Space Systems Company (LMSSC) conceived, designed, analyzed, assembled, tested, and integrated the optical assemblies for the NIRCam instrument. With using examples from NIRCam, this paper covers techniques for mounting small mirrors and lenses for cryogenic space missions.

Two precision mirror gimbals were designed using slit diaphragm flexures to provide two-axis precision mirror alignment in space-limited applications. Both gimbals are currently in use in diagnostics at the National Ignition Facility: one design in the Gamma Reaction History (GRH) diagnostic and the other in the Neutron Imaging System (NIS) diagnostic. The GRH gimbal has an adjustment sensitivity of 0.1 mrad about both axes and a total adjustment capability of ±6°; the NIS gimbal has an adjustment sensitivity of 0.8 μrad about both axes and a total adjustment range of ±3°. Both slit diaphragm flexures were electro-discharge machined out of high-strength titanium and utilize stainless steel stiffeners. The stiffener-flexure design results in adjustment axes with excellent orthogonality and centering with respect to the mirror in a single stage; a typical two-axis gimbal flexure requires two stages. Finite element analyses are presented for both flexure designs, and a design optimization of the GRH flexure is discussed.

Aluminum mirrors offer the advantages of lower cost, shorter fabrication time, more rugged mounting, and same material athermalization when compared to classical glass mirrors. In the past these advantages were offset by controversial dimensional stability and high surface scatter, limiting applications to IR systems. Raytheon developed processes to improve long term stability, and reduce surface scatter. Six 380 mm aperture aluminum mirrors made using these processes showed excellent stability, with figure changes of less than 0.01 wave RMS(1 wave = 633 nm) when cycled 10 times between -51 and +71 deg. C. The VQ process developed at ELCAN reduces surface scatter in bare aluminum mirrors to below 20 angstroms RMS, and has been used in thousands of production mirrors up to 300 mm aperture. These processes were employed in the fabrication of two lightweight single arch 600 mm aluminum mirrors. The two mirrors were produced in four months, with a mounted surface figure of 0.22 waves RMS and surface roughness of 20 angstroms. Mounted fundamental frequency was 218 Hz, and no figure distortion was observed at preload levels four times higher than design. Subsequently the mirrors performed well when subjected to severe environmental loadings in a Raytheon test system. This technology is being extended to ultra-lightweight sandwich mirrors, which are competitive with other material technologies used in advanced aerospace applications such as high-altitude UAV surveillance systems and satellite optics.

Recent game-changing technology greatly extends the design possibilities and range of applications for aggressively lightweighted open-back Zerodur® mirrors. We have compared several lightweighting design approaches under this new technology. Analytic comparisons are for 1.2m mirrors, all constrained to have a free-free first Eigenfrequency of 200 Hz. Figures of merit include resulting mass, thickness and relative cost. Much more aggressive masses are now available in open-back mirrors, competitive with the more expensive closed-back sandwich mirrors. These breakthroughs are relevant to spaceborne implementation of lightweight mirrors ranging from a few tenths of a meter in diameter to up to 4 meters in diameter.

The stability of lines of sight for imaging optics and lines of propagation for illuminators and lasers are determined by the structural load paths that support and connect them. The optical effects are coupled to the structure by the influence coefficients in the Optomechanical Constraint Equations. This paper shows how the optomechanical engineer can use mathematical spread sheets and finite element codes to combine the optical influence coefficients of the lines of sight and lines of propagation with the displacements of a structural analysis to predict (and minimize) pointing and bore sight errors in a suite of instruments.

In this semi-spherical meter, a single detector is used to realize all measurements, which is located on the extreme of a rectangular ring (assumed as joined two mobile branches in order to compensate the weights), describing half-meridians from 0° up to 170°. The illumination source under test is located at the center of the mobile support, which can rotate 360° horizontally. The two combined movements allow us to obtain a semi-spherical geometry. The number of measurement points is determined by the two step-motors located under the mobile support of the luminary and on one of the two fixed arms, which support the mobile rectangular ring, respectively. The mechanical arrangement has the enough rigidity to support the precision required for the acquisition stage, based on a dsPIC. The main advantages of this arrange are: Its low costs (using recyclable materials only such as "electronic waste"), a reliable detection based on a single photo-detector, with an integrated amplification stage, and the mechanical design. The received power by the detector is useful to obtain the irradiance profile of the lighting sources under test. The semi-spherical geometry of the meter makes it useful for the analysis of directive and non directive sources, in accordance with the angle described by the mobile ring. In this work, special attention is given to LED lamps due to its impact in several sceneries of the daily life. A comparison between the irradiance patterns of two LED lamps is also given.

In October 2009, a quad, mini-beam collimator was implemented at GM/CA CAT that allowed users to select between a 5, 10, or 20 micron mini-beam or a 300 micron scatter guard for macromolecular crystallography. Initial alignment of each pinhole to the optical axis of each path through the mini-beam collimator is performed under an optical microscope using an alignment jig. Next, the pre-aligned collimator and its kinematic mount are moved to the beamline and attached to a pair of high precision translation stages attached to an on-axis-visualization system for viewing the protein crystal under investigation. The collimator is aligned to the beam axis by two angular and two translational motions. The pitch and yaw adjustments are typically only done during initial installation, and therefore are not motorized. The horizontal and vertical positions are adjusted remotely with high precision translational stages. Final alignment of the collimator is achieved using several endstation components, namely, a YAG crystal at the sample position to visualize the mini-beam, a CCD detector to record an X-ray background image, and a PIN diode to record the mini-beam intensity. The alignment protocol and its opto-mechanical instrumentation design will be discussed in detail.

We present a simple and practical method for joining pneumatically floated optical tables. In order to demonstrate this method we joined two optical tables in an uncentered "T-shape", and used a Michelson interferometer to compare the stability of the entire "T-structure" versus one of its parts alone finding that they both show similar rigidity. We also found the optimal master-slave leg configuration by calculating the stress on the joint and confirmed the calculations by Michelson interferometry. The vibration damping for the "T-structure" against the unjoined tables was measured finding comparable results. This method can significantly reduce costs of large optical tables and will be useful to extend existing optical tables without manufacturer modification.

A dynamic microfluidic iris is realized. Light attenuation is achieved by absorption of an opaque liquid (e.g. black ink). The adjustment of the iris diameter is achieved by fluid displacement via a transparent elastomer (silicone) half-sphere. This silicone calotte is hydraulically pressed against a polymethylmethacrylate (PMMA) substrate as the bottom window, such that the opaque liquid is squeezed away, this way opening the iris. With this approach a dynamic range of more than 60 dB can be achieved with response times in the ms to s regime. The design allows the realization of a single iris as well as an iris array. So far the master for the molded silicone structure was fabricated by precision mechanics. The aperture diameter was changed continuously from 0 to 8 mm for a single iris and 0 to 4 mm in case of a 3 x 3 iris array. Moreover, an iris array was combined with a PMMA lens array into a compact module, the distance of both arrays equaling the focal length of the lenses. This way e.g. spatial frequency filter arrays can be realized. The possibility to extend the iris array concept to an array with many elements is demonstrated. Such arrays could be applied e.g. in light-field cameras.

A potential cubesat payload for low resolution study of planet Earth from space is an optical imaging system. Due to budget, space, and time constraints, commercial photographic lenses of the double Gauss type are prime candidates for limited duration cubesat optics. However, photographic objectives are not designed to operate in a space environment and modifications are usually necessary. One method of improving optical performance of the objective over large temperature variations is by replacing the stock lens mount with a different material. This paper describes the thermo-opto- mechanical analysis of several lens mount materials for a double Gauss imaging system suitable for a cubesat.

This work presents a developing design of adjustable supporting mechanism of secondary mirror for airborne Cassegrain optical remote sensing instruments. Several datum surfaces and shims have been designed in this mechanism, shims and one of structural parts can be released and are properly grinded to the desired thickness. The proposed mechanism has been verified by an experimental model. The reassembled accuracy is 5 arcsecond and ±3 μm for orientation and position respectively. Furthermore, their adjustable accuracy can achieve 5 arcsecond and ±3 μm respectively, depending on grinding and measurement precision. The accuracy can drive the optical system performance to design specification. After verification, we confirm the proposed design of adjustable supporting mechanism can be applied to airborne Cassegrain optical systems, and has good potential in spaceborne applications.

We investigated the occurrence of small but significant inaccuracies in the temporal integrity of a commercial high-speed [rotating mirror] imaging system (a Cordin 550-62 camera). Utilizing a relatively straightforward hardware addition, independent measurements of the actual frame rate at the point of camera triggering were conducted, and then compared to the Cordin system's self-reported frame rate values for each recording. The present data thus represents a follow-up to our earlier preliminary report on this instrument's performance, where we initially discovered that disparities between the true and reported values could arise. Interestingly, the data trends observed in the present report suggest a disparity, the nature of which is consistent with the Cordin camera reporting a frame rate that arises a short time before the trigger event, i.e. that the system's sampling algorithm senses the frame rate with a finite pre-trigger implemented, which runs counter to the procedure suggested by the manufacturer. As well as presenting the context, and supporting evidence for our own conclusions, we also developed an approach to reduce the error in the reported values by a factor of 7, from an average of 0.78% +/- 0.04% to 0.11% +/- 0.08% over the present data set.