The GAIA satellite will make a 3-D map of our Galaxy with measurement accuracy of 10 microarcseconds using two astrometric telescopes. The angle between the lines-of-sight of the two telescopes will be monitored using the Basic Angle Monitoring system with 1 microarcsecond accuracy. This system will be an interferometer consisting of a number of small mirrors and beam splitters in Silicon Carbide. Silicon Carbide has very high specific stiffness and very good thermal properties (low CTE and high conductivity). It also is a very stable material. A possible concept design for this Basic Angle Monitoring system is subject of a PhD study performed at the Technische Universiteit Eindhoven and TNO Science and Industry (The Netherlands). To prove that this concept design meets the alignment and measurement stability requirements, the GAIA extreme stability optical bench is developed. It will consist of a fourfold Michelson interferometer with four separate optical paths, which will measure the stability of the optical bench and the individual optical components. Also thermal cycling experiments and vibrations tests will be performed. 'Absolute' position measurements of the optical components with respect to the optical bench after the vibrations test will be performed using markers. The GAIA extreme stability optical bench will be placed in a vibration damped vacuum tank in order to imitate the highly stable L2 space environment. The goal is to obtain the first results early 2006.

Using feedback control, a versatile optical trap can be constructed that can be used to control either the position of trapped objects or apply specified forces. Yet, while the design, development, and use of optical traps has been extensive and feedback control has played a critical role in pushing the state of the art, it is surprising to note that few comprehensive examinations of feedback control of optical traps have been undertaken. Furthermore, as the requirements are pushed to ever smaller distances and forces, the performance of optical traps reach limits. It is well understood that feedback control can result in both positive and negative effects in controlled systems. This paper discusses the performance and analytical limits that must be considered in the development and design of control systems for optical traps.

By using guide stars astronomers are able to detect very faint celestial objects that would otherwise be invisible. This however necessitates the simultaneous observations of two stars at the same time. A system called Star Separator will add this functionality to the ESO-VLTi. In case of the Unit Telescopes of the VLT this system has to be implemented in the existing infra structure while simultaneously fulfilling many functional requirements. The major one being that each set of stars have different relative positions while the star images rotate due to the earth rotation. About two years ago TNO Science and Industry started to design and build the Star Separators for the Auxiliary Telescopes for the ESO VLTi. Now the Unit Telescopes will also be equipped with Star Separators. Obviously the design is based on that for the Auxiliary Telescopes. However additional functionality had to be implemented to compensate for the effect of earth rotation because no de-rotator, as for the Auxiliary Telescopes, can be implemented. The presentation will explain the functionalities of the Star Separator and how the opto-mechanical design is done.

We developed a new optical element which integrates an off-axis diffractive grating and an on-axis refractive lens surface in a prism. With this optical element, the alignment tolerance can be improved by manufacturing technology of the grating based WDM device and is practicable for mass production. An 100-GHz 16-channel DWDM device which includes this optical element has been designed. Ray tracing and beam propagation method (BPM) simulations showed good performance on the insertion loss of 2.91±0.53dB and the adjacent cross talk of 58.02dB. The tolerance discussion for this DWDM device shows that this optical element could be practically achieved by either injection molding or the hot embossing method.

Prior publications have postulated a direct relationship between a change in temperature and the corresponding change in axial preload of the form ▵P = K₃▵T for a lens or series of lenses compressed with a force P_A between a cell shoulder and a retaining ring or flange at assembly. Equations previously derived for K₃ considered only the effects of bulk compression of the lens and stretching of the cell wall. Several other factors that help determine K₃ have recently been identified. Four of these potentially significant factors (localized deformations of the glass and metal surfaces within the elastic interface, deflections of the retainer and of the shoulder, and radial dimension changes of the lens and cell) are considered here. It is shown that neglecting these factors can lead to significant overestimation of the magnitude of K₃ for a given design and result in overestimation of temperature change effects on contact stress. An example of a selected lens mounting design cascading all of these mechanical effects illustrates the significance of this new theory. Reasonable correlation achieved between classical equations and FEA analysis for key aspects of the analysis lends credence to the theory. The advantage of providing controlled axial compliance in the mechanical design also is illustrated.

Inside the Star Separator system for the Unit Telescopes for the ESO-VLTi two mechanisms are implemented to compensate for the earth rotation that complicates the simultaneous and continuous observations of two stars. The function of the mechanisms is comparable to a de-rotator without the drawback of having to add three folding mirrors. One of the mechanisms is a scan mechanism with two independent orthogonal rotations. It makes use of flexures to eliminate play and to guarantee long term maintenance free operation. It also uses piezo stages for extreme accurate pointing (< 1μrad) for rotations of around 0.1 rad without hysteresis. The second mechanism realizes the optical star splitting being the primary function of the Star Separator.

A high bandwidth, gimbaled, fast steering mirror (FSM) assembly has been designed and tested at the Lockheed Martin Space Systems Company (LMSSC) Advanced Technology Center (ATC). The design requirements were to gimbal a 5 cm diameter mirror about its reflective surface, and provide 1 KHz tip/tilt/piston control while maintaining λ/900 flatness of the mirror. The simple, yet very compact and rugged device also has manual tip/tilt/piston alignment capability. The off-the-shelf Piezo translators (PZT) actuators enable reliable and repeatable closed loop control. The adopted solution achieves a good mass balance and gimbaled motion about the center of the mirror front surface. Special care was taken to insure the best positioning means with the mounted mirror assembly held kinematically in place. The manual adjusters have very good resolution, with the capability to be locked in place. All solutions were thoroughly modeled and analyzed. This paper covers the design, analysis, fabrication, assembly, and testing of this device. The FSM was designed for ground test only.

A new sounding rocket payload is being built at the University of Colorado for purposes of resolving spectral features in the diffuse x-ray background. Multiple grating mounts are required; each consisting of over sixty closely packed grazing incidence gratings to meet throughput goals. The rocket skin limits the payload envelope and volume for mounting the gratings. Packing geometries require the gratings be very thin. The gratings are mounted in an off-plane configuration much like a proposed scenario for the Constellation X reflection grating assembly. In this paper we discuss innovative fabrication, replication, and mount techniques used to support a spectral resolution goal of about 100 (λ/δλ).

This paper describes the design of a two sided aluminum tracking mirror and mechanism for the CONTOUR Remote Imager and Spectrometer (CRISP) instrument flown on NASA's COmet Nucleus TOUR (CONTOUR) spacecraft launched in July 2002. The tracking mirror mechanism was designed to operate in a -60°C high vacuum space environment. The primary structure of the instrument and the tracking mirror assembly were all fabricated from solid billets of magnesium ZK60A-T5 alloy. Interfacing materials with drastically different coefficients of thermal expansion required significant analysis and close attention to details. By maintaining close symmetry, tight but not unrealistic tolerances, and simultaneous machining of interfaces, we were able to keep thermal distortions virtually identical on both ends of the mirror axis and thus maintain mirror flatness to mission requirements.

Precise knowledge of the instrument boresight was required over the gimbal range for the CRISM Instrument (Compact Reconnaissance Imaging Spectrometer for Mars), which will fly aboard the Mars Reconnaissance Orbiter. Vector metrology techniques were applied to measure both the optical axis and the axis-of-rotation of the instrument housing about its mount (gimbal axis). Boresight stability was quantified through comparison of pre-environmental and post-environmental alignment data. In addition, checks were made of the instrument internal alignment and field-of-view. Distillation of the boresight data into gimbal axis and optical axis offset knowledge allowed the calculation of the instrument boresight at all gimbal settings. Finally, alignment information was mapped into the instrument reference cube, ensuring proper instrument orientation during installation.

We give an example of a Point Source Microscope (PSM) and describe its uses as an aid in the alignment of optical systems including the referencing of optical to mechanical datums. The PSM is a small package (about 100x150x30 mm), including a point source of light, beam splitter, microscope objective and digital CCD camera to detect the reflected light spot. A software package in conjunction with a computer video display locates the return image in three degrees of freedom relative to an electronic spatial reference point. The PSM also includes a Koehler illumination source so it may be used as a portable microscope for ordinary imaging and the microscope can be zoomed under computer control. For added convenience, the laser diode point source can be made quite bright to facilitate initial alignment under typical laboratory lighting conditions. The PSM is particularly useful in aligning optical systems that do not have circular symmetry or are distributed in space such as off-axis systems. The PSM is also useful for referencing the centers of curvatures of optical surfaces to mechanical datums of the structure in which the optics are mounted. By removing the microscope objective the PSM can be used as an electronic autocollimator because of the infinite conjugate optical design.

Medium-sized Aperture Camera (MAC) is the main payload for Earth observation satellite RazakSAT to be launched at the end of 2005. The flight model has been recently assembled and tested. The 300 mm diameter Cassegrain telescope optics and the focal plane assembly for a space camera have been aligned. Topics discussed in this paper include the lessons learned from the optics alignment and assembly of the telescope and the focal plane. A computer-aided alignment method was used for the alignment of the relatively wide field of view (+/-1 deg) telescope. RMS wavefront error measurement environment was found to be more critical than previously experienced, and the importance of the initial alignment is discussed. System modulation transfer function (MTF) was used as the figure-of-merit for the alignment of the focal plane assembly with linear CCD detectors. MTF was measured by a knife-edge scanning technique using a dedicated 450 mm diameter collimator with diffraction-limited performance.

One of the greatest challenges in the packaging of laser modules using laser welding technique is to use a reliable and accurate joining process. However, during welding, due to the material property difference between welded components, the rapid solidification of the welded region and the associated material shrinkage often introduced a post-weld-shift (PWS) between welded components. For a typical single-mode fiber application, if the PWS induced fiber alignment shift by the laser welding joining process is even a few micrometers, up to 50 % or greater loss in the coupled power may occur. The fiber alignment shift of the PWS effect in the laser welding process has a significant impact on the laser module package yield. Therefore, a detailed understanding of the effects of PWS on the fiber alignment shifts in laser-welded laser module packages and then the compensation of the fiber alignment shifts due to PWS effects are the key research subjects in laser welding techniques for optoelectronic packaging applications. Previously, the power losses due to PWS in butterfly-type laser module packages have been qualitatively corrected by applying the laser hammering technique to the direction of the detected shift. Therefore, by applying an elastic deformation to the welded components and by observing the corresponding power variation, the direction and magnitude of the PWS may be predicted. Despite numerous studies on improving the fabrication yields of laser module packaging using the PWS correction in laser welding techniques by a qualitative estimate, limited information is available for the quantitative understanding of the PWS induced fiber alignment shift which can be useful in designing and fabricating high-yield and high-performance laser module packages. The purpose of this paper is to present a quantitative probing of the PWS induced fiber alignment shift in laser-welded butterfly-type laser module packaging by employing a novel technique of a high-magnification camera with image capture system (HMCICS). The benefit of using the HMCICS technique to determine the fiber alignment shift are quantitatively measure and compensate the PWS direction and magnitude during the laser-welded laser module packages. This study makes it possible to probe the nonlinear behavior of the PWS by using a novel HMCICS technique that results in a real time quantitative compensation of the PWS in butterfly-type laser module packages, when compared to the currently available qualitatively estimated techniques to correct the PWS2. Therefore, the reliable butterfly-type laser modules with high yield and high performance used in lightwave transmission systems may thus be developed and fabricated.

We have developed a prototype instrument with a novel interferometrically controlled differential scanning stage system. The system consists of 9 DC-motor-driven stages, 4 picomotor-driven stages, and 2 PZT-driven stages. A custom-built laser Doppler displacement meter system provides two-dimensional (2D) differential displacement measurement with subnanometer resolution between the zone-plate x-ray optics and the sample holder. The entire scanning system was designed with high stiffness, high repeatability, low drift, flexible scanning schemes, and possibility of fast feedback for differential motion. Designs of the scanning stage system, as well as preliminary mechanical test results, are presented in this paper.

Flexures are more reliable than bearings for long-life mechanisms with small magnitude motions. Typically made of metallic materials, a portion of the flexure is thinned dramatically to provide flexibility in the desired degree-of-freedom. When used in space-based remote sensors, the flexure also needs to survive launch-induced loads. The thinned sections act as stress risers in the part, which are susceptible to failure during launch vibration loading. The flexure in a new infrared remote sensor catastrophically failed during a mass model vibration test. The flexure design was then revised using a L9 orthogonal array with one noise factor. Two quality characteristics were evaluated, and the critical characteristic, peak stress level, was analyzed using a Smaller-the-Better signal-to-noise (S/N) ratio. A material study was conducted independently of the robust design experiment to validate the material selection for the application. The design effort was complicated by the constraint to leave the flexure rotational stiffness unchanged while simultaneously improving the load carrying capability. If this requirement was ignored, the Taguchi experiment would have been quite successful, with a 98% improvement in the S/N ratio. However, this improved configuration was not feasible since it significantly affected the rotational stiffness. The primary benefit from the experiment was to identify a path for further design changes, and the relative importance of several control factors. The design was completed within three days using one-at-a-time iterations of two additional control factors. The final flexure design has a S/N ratio as high as the experiment-recommended configuration without the change in rotational stiffness. Detailed structural analysis using a correlated model shows that all design requirements are satisfied, and the new flexure has been validated by a random vibration test.

We have designed and tested a new digital signal processor (DSP)-based closed-loop feedback controller for a linear actuator system with sub-angstrom resolution and 15-mm travel range. The linear actuator system consists of a laser Doppler encoder with multiple-reflection optics [1], a high-stiffness weak-link mechanism with high driving sensitivity and stability [2], and a Texas Instruments TMS320C40 DSP-based controller for high-performance closed-loop feedback control. In this paper, we discuss the DSP-based controller design, as well as recent test results yielding step sizes below 50 picometers obtained with the atomic force microprobe setup.

A revolute-joint robot is being developed for the spatial positioning of an x-ray detector at the Advanced Photon Source. Commercially available revolute-joint manipulators do not meet our size, positioning, or payload specifications. One idea being considered is the modification of a commercially available robot, with the goal of improving the repeatability and trajectory accuracy. Theoretical, computational, and experimental procedures are being used to (1) identify, (2) simulate the dynamics of an existing robot system using a multibody approach, and eventually (3) design an improved version, with low dynamic positioning uncertainty. A key aspect of the modeling and performance prediction is accurate stiffness and damping values for the robot joints. This paper discusses the experimental identification of the stiffness and damping parameters for one robot harmonic drive joint.

The design and development of a beam launch telescope (BLT) was addressed herein. The BLT optical instruments have been commonly used for the applications of adaptive optics (laser guide star), optical communications, and other laser powered optical systems. In this study, a BLT with a primary mirror of 700 mm was investigated as a prototype optical system. The BLT optical system includes a lightweight primary mirror of 700 mm in daimeter, a secondary mirror of 110 mm, a fast steering mirror of 200 mm, and three flat mirrors (array/relay mirrors) of 200 mm. As a test bed, the BLT system was optimized for a spot size of 100mm at a far field (departed by 1km from the telescope). In this design and development study, a wide range of the opto-mechanical and structural analyses have been performed including: static (gravity and thermal), frequency, dynamic and response analysis, and optical evaluations for minimum optical deformation. The EDS I-DEAS Finite Element program and the PCFRINGE optical program are mainly used to fulfill this analysis. Image motion is also calculated based on line of sight (LOS) sensitivity equations integrated in finite element models.

Optical spectroscopy is a common tool for many applications. Micro systems most often use fixed gratings and array detectors. In the infrared wavelength range above the limit for Si-detectors (1100nm) and Ge-detectors (1700nm) respectively, this is either very expensive or almost impossible. Micro opto electro mechanical systems (MOEMS) offer very promising options. A movable grating can be realized by a silicon chip, using the technology of a well established scanner mirror chips in combination with the realization of a reflective grating either through etching of the aluminium mirror layer or even a more sophisticated technology. The patented resonant drive realizes a mechanical angle of ±7° with CMOS compatible voltages of approximately 20V. This technology leads to the realization of a set up close to a classical Czerny-Turner spectrometer using a single detector only. The device offers the capability to be scaled down to the size of a cigarette box. The spectrometer presented here was adjusted to 900...2500nm range. The scanning grating chip has either 500, 625 or 714 lines/mm. As detector serves a fast InGaAs photodiode, read out through a 12 Bit AD converter. The sinusoidal movement is unfolded by a signal processor (TI TMS320F2812) which also computes the spectrum. Acquired data can be shown by a display or transmitted to a host PC. System tests have been performed using infrared LEDs. Wavelengths have been 1300, 1400 or 1550nm for example. The spectrometer is working accurately. First result of micro shaped grating structures to enhance the sensitivity are presented.

Unpolished diamond turned mirrors are common for infrared systems. We report the successful use of unpolished mirrors in a visible spectrum, all aluminum telescope for the planned New Horizons mission to Pluto. The Ralph telescope is an F/8.7 Three Mirror Anastigmat with a 75mm aperture, a 5.7° by 1.0° field of view, and a mass of only 8kg. Key to the performance of the system are a process for reducing the micro-roughness of the off-axis aspheric surfaces to below 60 Ångstroms RMS, and the fabrication of precision diamond turned mounting features on the mirrors and one-piece, thin-walled housing. The telescope achieves nearly diffraction-limited performance with minimal post-assembly alignment, and maintains that performance, including focus, over a wide range about the operating temperature of 210K.

The development of the optimum locations of actuators for an adaptive optic has in the past been a manually iterative process. Such a manual process becomes fruitless when multiple disturbance cases (e.g., gravity and thermoelastic deformations) need to be considered in the development of a single actuator layout. A more automated yet efficient method is desired to quickly develop an optimum actuator layout and the associated optical performance. A genetic design optimization algorithm is developed and implemented in software. The method is then demonstrated on an example adaptive optic design to show how it can be used to develop optimum actuator layouts for a fixed number of actuators or to conduct design trades in choosing the number of actuators.

Traditionally, instruments for astronomical telescopes are built in Aluminium plate structures, but with the increasing demand for complexity and consequent increase in mass (e.g. the instruments for Very Large Telescopes (VLT) and the future eXtremely Large Telescopes (XLT)), lightweight structures of Carbon Fibre Reinforced Plastic (CFRP) become attractive. CFRP-structures give higher stiffness per unit weight and are less sensible to temperature variations. As an example the performance of a CFRP lattice structure for the ESO VLT X-shooter instrument is compared with the present design of the Aluminium.

One of the major challenges for typical opto-mechanical assemblies is that they require multiple degrees of freedom with large travel (several millimeters) but very small (sub-micron) resolution. After adjustment, assemblies must be stable to a few nanometers to survive environmental and mechanical shock over a lifetime of use. Using parts with engineered mating surfaces, we have developed a low-cost and robust set of components with demonstrated sub-50-nm adjustment resolution and comparable stability after multiple environmental stress events. For this work, we have adopted -30 to +70 C temperature cycling and 10 G (15 ms) half-sine shock as our environmental qualification standards. We apply the methodologies of reliability testing learned for Telcordia qualification of passive fiber optic components to opto-mechanical components and assemblies for capital equipment instruments. Demonstration of sub-50-nm resolution and stability for our developed opto-mechanical components requires a suitable test stand, which we have developed using scanning knife-edge beam profilers and a highly-repeatable kinematic loading base with a built-in reference. We use these test results to develop system error budgets in design and manufacture based on component, assembly, and measurement tolerances. The developed opto-mechanical assemblies have been demonstrated to have sub-50 nm stability in laboratory and field tests.

With a 4 m off-axis aspherical primary mirror, integrated adaptive optics, low scattered light, infrared coverage, and state-of-the-art post focus instrumentation, the Advanced Technology Solar Telescope (ATST) will be the world's most powerful solar research telescope. In order to achieve the required performance specifications of the telescope, the ATST project selected an alt-az telescope mount to support and position the major optic assemblies. In addition, the telescope incorporates a large diameter (16.4m) coude rotator lab that is capable of supporting multiple large instrument assemblies. This lab can rotate about its azimuth axis independent of the alt/az mount above it. In this paper, we describe an overview of the telescope structure, discuss the basic design parameters, and summarize the results of initial finite element analyses. The results include static analyses (gravity and average static wind loading), telescope natural modes, dynamic response to wind loadings, and a seismic loading analysis. Image motion at the instrument focal plane is also calculated based on line of sight (LOS) sensitivity equations integrated into the finite element models.

In December 2004 the European Consortium that develops the optical bench assembly for MIRI successfully passed the Preliminary Design Review. MIRI is the combined imager and integral field spectrometer for the 5-28 micron wavelength range under development for the JWST. After this PDR milestone the optical design of the MIRI spectrometer is now implemented in a compact, modular mechanical design that puts all optical elements in place within the required tolerances. Many aspects of this design are based on the heritage of previous instruments developed at ASTRON, in particular the cryogenic optics for the mid-IR VLT instruments VISIR and MIDI, but several adjustments to this design philosophy were made to develop the necessary space-qualified light-weighted components. Prototyping of these components has now started. This paper describes trade-offs and solutions for the opto-mechanical design of the optics (gratings, mirrors and their mountings) and of the main structure of the spectrometer, taking into account optical performance, manufacturability, cost and lead times. It also addresses the complex interface management in a large international consortium and reports first prototype results.

This paper describes the design of the compact, lightweight, and athermalized Pick Off Mirror and Mount. Structural and thermal analysis as well as actual prototype testing are also described.

This Paper will discuss the design of a triple redundant cryogenically cooled and isolated Focal Plane Assembly (FPA) for the Compact Remote Imaging Spectrometer for Mars (CRISM) instrument. The FPA is required to operate in the temperature range of 90 - 100K. The CRISM FPA isolation system was constructed from a ceramic fiber composite. The FPA was cooled by one of three cryocoolers individually connected to one of three diode heat pipes that were all connected to the FPA. The total heat load imposed by the isolation system was about 250 milliwatts at operating temperature. CRISM is expected to launch in August of 2005.

Single crystal Lithium Fluoride has been base-lined as one of the optical materials for the Near Infra-Red Camera (NIRCam) on the James Webb Space Telescope (JWST). Optically, this material is outstanding for use in the near IR. Unfortunately, this material has poor mechanical properties, which make it very difficult for use in any appreciable size on cryogenic space based instruments. In addition to a dL/L from 300K to 30K of ~-0.48%, and a room temperature CTE of ~37ppm/K, the material deforms plastically under relatively small tensile loading. This paper will present a mount that has been proven via vibration and thermal-vacuum testing to successfully mount a large (70mm-94mm) Lithium Fluoride optic for application in space. An overview of Lithium Fluoride material properties and characteristics is given. A design limit load is determined for the material based on strength values from the literature as well as independent testing. The original design option is shown and the pros and cons discussed. The final mount design is then presented along with analysis results showing compliance to the limit load requirement. Finally, testing results are discussed showing survival of the optic in a space launch vibration environment as well as survival during cool-down to the operational thermal environment of 30K.

This paper presents the TNO share of the development of the HIFI Alignment Camera System (HACS), covering the opto-mechanical and thermal design. The HACS is an Optical Ground Support Equipment (OGSE) that is specifically developed to verify proper alignment of different modules of the HIFI instrument during on-ground thermal (vacuum) testing of the ESA Herschell spacecraft.

The segment prototype of the active Schmidt plate segment of the Large sky Area Multi-Object Spectroscopic Telescope (LAMOST) was setup and measured. Nanometer displacement actuator with resolution of 50 nm was used for displacement inputting and both normal capacitive displacement sensors with resolution of 4.2 nm, and differential capacitive displacement sensors with resolution of 5 nm, for displacement reading. For the output displacements of the segment demands for finer displacement increment, three independent groups of lever reducing mechanism with reduction ratio of 1/4 were introduced in the prototype, and the measurement was to test the actuation transmitting performance of the lever systems. Theoretical actuation transfer formula were given and compared with measured data at three typical pointing angles of the segment prototype. The raw data were well corrected with extrapolation technique by monitoring temporal environmental influence on measurement system. The results confirmed that the actuation transmitting performance was as good as required. Its ultimate reducing transmitting ratio is very linear and stable, close to theoretical 3.047 within relative error of 6%, which is easy to be corrected by close-loop control for each segment of the active optics in LAMOST. Also, the measurement process proved itself that the differential capacitive displacement sensor be capable for the application to the active optics in the LAMOST.

The reflecting Schmidt plate of the Large sky Area Multi-Object Spectroscopic Telescope (LAMOST) is segmented with 24 thin hexagonal sub-mirrors of 1.1 meters tip-tip each. It not only serves as active corrector for eliminating spherical aberration of the fixed segmented spherical primary mirror but also collaborates with focal plane in between to do pointing and tracking with an alt-azimuth mounting. This paper describes the evolution and evaluation of the structural design of the reflecting Schmidt mirror cell onto which sub-mirror systems are connected. Technical requirements are presented before a brief history of evolution of the mirror cell throughout the progress of the LAMOST project. Based on final elevation driving and balancing scheme, a final design of the mirror cell has been reached and evaluated with finite element method. Following the principle of deflection-independent, the design is actually a hybrid of space frame and truss structure meeting technical requirements with low weight, high stiffness and clear accessibility. Gravitational analysis results that the maximum deflection is about 1 mm through overall observing sky area of -10°≤δ≤90°, and modal extraction finds that the lowest eigenfrequency is about 30 Hz. Relevant investigation of elevation axis trunnion preload and driving force effect as well as evaluation of typical thermal and static wind disturbance also confirm the excellent performance of the final design of the Schmidt mirror cell.

The CALIPSO LIDAR utilizes a receiver telescope with a narrow Field-of-View (FOV) to reject background light and meet SNR requirements - FOV ≈ 130 μrad. To maximize SNR the laser is collimated (divergence ≈100 μrad) and must be aligned to the receiver telescope FOV to within +/- 12 μrad (allocated). To make accurate LIDAR measurements the receiver/laser alignment must not vary by more than +/- 10 μrad (allocated) over an orbit. To make accurate depolarization measurements of clouds, the polarization axis of the laser must be aligned to within +/- 0.5 degrees (allocated) relative to the aft optical bench polarization axis and maintain alignment throughout the motion of the boresight adjustment range. The Active Boresight Mechanism provides a means of re-aligning the laser to the telescope on-orbit. A comprehensive performance testing campaign demonstrated that the Active Boresight Mechanism met or exceeded requirements. On-orbit performance results are imminent, as CALIPSO is scheduled for launch this Fall.

EMIR is a NIR multiobject spectrograph with imaging capabilities to be used at the GTC. The first collimator lens in EMIR, made of Fused Silica, has an outer diameter of 490 mm, and a weight of 265 N, which make it one of the largest Fused Silica lenses ever mounted to work under cryogenic conditions. The results of the various tests being done at the IAC (with two different lens dummies) in order to validate a mounting design concept for this lens, are presented here. The radial support concept tested consists of three contact areas around the lens, one of which is a PTFE block, preloaded by coil springs and the other two are fixed supports made of Aluminum and PTFE, dimensioned in order to keep lens centered both at room temperature and under operation conditions.

We are proposing a novel application for fiber optic sensors in measuring acceleration. This novel design accelerometer is based on a fiber Bragg grating (FBG). The device we are proposing is capable of measuring acceleration in three axes simultaneously.

The confocal imaging has become one of the most widely applied microscopic techniques in various fields, such as biotechnology, automation engineering, optical engineering, solid-state physics, metallurgy, integrated circuit inspection, etc. Confocal laser scanning microscopy (CLSM) is primarily based on the use of apertures in the detection path to provide the acquired three-dimensional images with satisfactory contrast and resolution. The major objective of this paper is to analyze the imaging performance of the confocal microscopes with varying opto-mechanical conditions. In this paper, the working principles of the one- and two-dimensional scanning mechanisms in the microscopic systems are first reviewed and verified by opto-mechanical simulations. Then, for the imaging performance, the tolerance to the fabrication and assembly of the optical components in conventional confocal microscopes is also investigated by simulations. The simulation results indicate the importance of eliminating the effects of stray light in the microscopic systems.

The 3m Spherical Primary Optical Telescope (SPOT) will utilize a single ring of 0.86 m point-to-point hexagonal mirror segments. The f2.85 spherical mirror blanks will be fabricated by the same replication process used for mass-produced commercial telescope mirrors. Diffraction-limited phasing will require segment-to-segment radius of curvature (ROC) variation of ~1 micron. Low-cost, replicated segment ROC variations could be almost 1 mm, necessitating a method for segment ROC adjustment & matching. A mechanical architecture has been designed that allows segment ROC to be adjusted up to 400 microns while introducing a minimum figure error, allowing segment-to-segment ROC matching. A key feature of the architecture is the unique back profile of the mirror segments. The back profile of the mirror was developed with shape optimization in MSC.Nastran™ using optical performance response equations written with SigFit. A candidate back profile was generated which minimized ROC-adjustment-induced surface error while meeting the constraints imposed by the fabrication method.