This PDF file contains the front matter associated with SPIE Proceedings Volume 8491 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

A microoptical 3D interconnection scheme and fabricated samples of this fiberoptical multi-channel interconnec- tion with an actual capacity of 144 channels were shown. Additionally the aspects of micrometer-fabrication of such microoptical interconnection modules in the view of alignment-tolerances were considered. For the realiza- tion of the interconnection schemes, the approach of planar-integrated free space optics (PIFSO) is used with its well known advantages. This approach offers the potential for complex interconnectivity, and yet compact size.

In designing optical systems where the eye serves as the final detector, assumptions are typically made regarding the optical quality of the eye system. Often, the aberrations of the eye are ignored or minimal adjustments are built into the system under design to handle variations in defocus found within the human population. In general, the eye contains aberrations that vary randomly from person to person. In this investigation, a general technique for creating a random set of aberrations consistent with the statistics of the human eye is developed. These aberrations in turn can be applied to a schematic eye model and their effect on the combined visual instrument/eye system can be determined. Repeated application of different aberration patterns allows for tolerance analysis of performance metrics such of the modulation transfer function (MTF).

The tolerances are given to keep the performance criteria within the acceptable values in the manufactured lenses. If the tolerances and the performance criteria are given, the yield of the manufacturing can be estimated with the Monte Carlo simulation. The tolerance determines the manufacturing cost. The manufacturing cost should be as low as possible. The cost-based tolerancing is to determine the tolerances accounting for the manufacturing cost. This optimization problem looks complicated and time-consuming when the yield is viewed as a function of the tolerances. The author found the problem is dramatically simplified if the variances or averages of the critical performance criteria are used as the independent variables of the optimization. The optimal tolerance set can be found with a few trials of the Monte Carlo simulation.

X-ray telescope architectures currently being examined for future missions such as concepts like the International X-ray Observatory (IXO) are composed of thousands of extremely thin mirror elements (0.2 to 0.4 mm thick) arranged in closely spaced arrays. The precise positioning, integration, and testing of those optical elements are some of the fundamental challenges for fabrication of future X-ray telescopes. We will describe a novel pneumatic actuator and initial testbed results for positioning a single mirror and subsequently an array of mirrors.

The ATLAS Instrument for the ICESat-2 mission at NASA's Goddard Space Flight Center requires a test-bed to prove out new concepts before the mission launches in 2016. The Optical Development System (ODS) laboratory was created to use breadboard, prototype, and engineering-model levels of hardware and software to model and evaluate the ATLAS alignment system. A one meter parabolic mirror was used to create a collimated light beam to align prototype and engineering model transmitter and receiver optics and test closed-loop alignment algorithms. To achieve an error of less than two micro-radians, an active deformable mirror was used to correct the wave front to subtract out the collimator mount error.

Stray light analysis of FormoSat-5 telescope has been studied. The geometric contour profiles of the baffles are determined by checking the degree of blocked direct-incidence stray light. Trade-off between different baffle contours has been made by comparing the direct-incidence stray light, incident energy ratio, and incident energy uniformity of the focal plane assembly (FPA). Detail studies have then performed on the contribution of the stray light due to direct incidence, scattering from components, and multi-reflection between optical components. The effect of the FPA structure is also considered since it is the component adjacent the most to the FPA. In addition, the tolerance of the baffles fabrication and assembly are introduced.

Gas correlation imagers are important instruments for remotely detecting effluent emissions. However, making a functional design for field testing is non-trivial given the range of environmental conditions the system may be operated under and the required matched imaging performance for both channels. We present a dual channel 7 degree full field of view f/2.5 athermal optical design athermalized from 0 to 50 degrees C that operates in the wavelength range of 2.0 to 2.5 microns suitable for methane imaging. We present the optical design, tolerance budget, and alignment plan used for the system. Predicted and as-built performance data including interferometric and ensquared energy measurements for both imaging channels are also shown.

While some instrument requirements are levied on a per-pixel basis, efficiencies and economies can be gained by testing them in parallel. Furthermore, the use of detector arrays as imagers with extended targets enables the derivation of geometrical information from select pixels in each image, and its propagation to neighboring pixels. We discuss the implementation of one such test regime for the Operational Landsat Imager (OLI) at Ball Aerospace and Technologies Corp. This enabled rapid measurement of spatial parameters, including Edge Response Function and aliasing, for all of the nearly 70,000 active pixels of the focal plane assembly with reduced reliance on the precision and stability of the supporting equipment. The derived geometrical information enabled us to replace a step-stare testing of individual pixels with a continuous scan of the entire assembly, without demanding precision motion or introducing noise from variations in the scan velocity. Three complete scans were performed in under 30 hours.

The Navy's ground-based optical interferometer requires 10 discrete reflections for each of its six stations that transport stellar radiation into a six-way beam combiner where the modulated beams are overlapped in a collinear fashion and fringes obtained for analysis. Wavefront aberrations, introduced at each reflection from non-perfect mirrors, reduce the quality of fringe contrast and adversely affect the final science results. In practice, mirror fabrication and mounting methods generate small surface irregularities that produce aberrations in the reflected wavefront beam. Under multiple reflection scenarios, these errors do not necessarily cancel one another, and can increase the resultant wavefront distortion. In a previous paper, we showed a single-force actuator acting on the back surface of an 8-inch diameter Zerodur® mirror will achieve a canceling deformation in the reflective surface that substantially reduces the combined wavefront aberrations resulting from a 7-reflection beam. Our finite element model demonstrated that the peak-to-valley difference can be reduced from 210 nm to 55 nm. In this paper, we extend our previous work to include a support structure to contain the deforming mirror and analyze its interaction and effect on the corrected wavefront. Our design used the mechanical advantage gained from a tuned flexure plate with a simple motorized screw actuator applied to the back mirror surface to achieve an 87:1 deflection ratio on the front mirror surface. A practical design is proposed, the support structure and mirror analyzed using the finite element method, and the results presented and discussed.

The National Ignition Facility (NIF) requires high resolution live images of regions inside the target chamber in order to align diagnostic instruments to fusion targets and to monitor target stability. To view the interior of the target chamber, we modified a commercial 11-inch Schmidt-Cassegrain telescope to develop the Opposed Port Alignment System (OPAS). There are two OPAS systems installed on the target chamber ports directly opposite the diagnostics. This paper describes the optical design, highlighting the two key modifications of the telescope. The first key modification was to reposition the Schmidt corrector plate and to uniquely mount the secondary mirror to a precision translation stage to adjust focus from 5.5 m to infinity. The stage is carefully aligned to ensure that the telescope’s optical axis lies on a straight line during focus adjustments. The second key modification was a custom three element lens that flattens the field, corrects residual aberrations of the Schmidt-Cassegrain and, with a commercial 1:1 relay lens, projects the final image plane onto a large format 50 mega-pixel camera. The OPAS modifications greatly extend the Schmidt-Cassegrain telescope’s field of view, producing nearly diffraction-limited images over a flat field covering ±0.4 degrees. Also discussed in the paper are the alignment procedure and the hardware layout of the telescope.

Previous works have shown the viability of using the Sine Condition Test (SCTest) to verify the alignment of optical systems. The SCTest uses the Abbe sine condition to measure the mapping between the entrance and exit pupils of an optical system. From this pupil mapping, the linearly-field dependent aberrations can be measured and used to verify the alignment. Specifically, the linear astigmatism is used as a metric to determine how well the optical system is aligned. An advantage to using the sine condition to measure the off-axis performance is that the measurement equipment can be placed on-axis. By doing this, the uncertainty of the measurement is reduced, making this test especially useful for verifying systems with large inherent aberrations. In this paper, we expand the design space of the SCTest by exploring the two different source options: a point source with a grating or a flat-panel display. Additionally, we show experimental results of implementing the SCTest using a flat-panel display. Last, we explain how the SCTest can be implemented on more complex systems, such as a three-mirror anastigmat (TMA) and a double Gauss. By exploring the design space, we provide more design options for selecting the SCTest source, increasing the flexibility and utility of the SCTest.

As binocular enthusiasts share their passion, topics related to collimation abound. Typically, we find how observers, armed only with a jeweler’s screwdriver, can “perfectly collimate” his or her binocular, make it “spot on,” or other verbiage of similar connotation. Unfortunately, what most are addressing is a form of pseudo-collimation I have referred to since the mid-1970s as “Conditional Alignment.” Ignoring the importance of the mechanical axis (hinge) in the alignment process, this “condition,” while having the potential to make alignment serviceable, or even outstanding—within a small range of IPD (Interpupillary Distance) settings relative to the user’s spatial accommodation (the ability to accept small errors in parallelism of the optical axes)—may take the instrument farther from the 3-axis collimation conscientious manufacturers seek to implement. Becoming more optically savvy—and especially with so many mechanically inferior binoculars entering the marketplace— the consumer contemplating self-repair and alignment has a need to understand the difference between clinical, 3-axis “collimation” (meaning both optical axes are parallel with the axis of the hinge) and “conditional alignment,” as differentiated in this paper. Furthermore, I believe there has been a long-standing need for the term “Conditional Alignment,” or some equivalent, to be accepted as part of the vernacular of those who use binoculars extensively, whether for professional or recreational activities. Achieving that acceptance is the aim of this paper.

Auto-stigmatic microscopes (ASM) are useful for bringing centers of curvatures of lenses and mirrors to the centers of balls used as part of an alignment fixture. However, setting up the fixture to get the balls used for alignment in a straight line to represent the optical axis generally requires another piece of equipment. We show that within a practical range, the autocollimation mode of a modern ASM can be used to align balls to an axis with about the same precision as they could be aligned with an alignment telescope, or laser tracker. As a lead in to this topic, we discuss our meaning of alignment, the means of positioning optically important features such as centers of curvature and foci to the coordinates specified on assembly drawings. Finally, we show a method of using an ASM along with other tooling to align a toroidal mirror using its foci.

Several computer-aided alignment (CAA) methods have been developed for the alignment of multi-element optical systems. Most of the methods use singular value decomposition or non-linear optimization to calculate the amount of misalignment. However, when we do the alignment of the optical system, we frequently encounter at least two problems; one is the solution stalled in local minima that fails to align the system within requirement and the other is the field imbalance of the system. We presume this is due to the lack of boundary conditions imposed during the optimization. In order to overcome these problems, we propose a new CAA method using rms wavefront error (WFE) value as an additional boundary condition in optimization. This boundary condition of target rms WFE helps to get around the local minima and field imbalance while guaranteeing the system performance. We applied this method to the alignment of the optical system consisting of three mirrors and four lenses. By only single trial of alignment, we obtained the rms WFE of less than λ /20 (λ=3390 nm) at all fields and field difference less than λ /200 in off-axis field. Therefore, it is clear that our new method is very effective and accurate, compared to the conventional CAA algorithm.

We introduce a design of an Offner imaging spectrograph with its performance and tolerancing results. It is a traditional Offner spectrograph employing two concave mirrors and one convex reflective grating for dispersing light in the SWIR band (900~1700 nm). The optical system uses 25um-pitch pixels for the detector and the goal spectral sampling is 3.2nm. Its performance is analyzed in terms of MTFs, spot diagrams, and distortions – keystone and smile. This design focuses on the yaw(beta-tilt) sensitivity of the tertiary mirror as the compensator hence is expected to act as a performance-improving breakthrough for the entire system as the inverse sensitivity confirms it is the most sensitive component. The procedure of the inverse sensitivity evaluation is explained, and then budgeting the tolerances for each element for the practical production is described.

In order to meet both optical performance and structural stiffness requirements of the aerospace Cassegrain telescope, iso-static mount is used as the interface between the primary mirror and the main plate. This article describes the alignment and iso-static mount bonding technique of the primary mirror by assistance of CMM. The design and assembly of mechanical ground support equipment (MGSE) which reduces the deformation of primary mirror by the gravity effect is also presented. The primary mirror adjusting MGSE consists of X-Y linear translation stages, rotation stage and kinematic constrain platform which provides the function of decenter, orientation, tilt and height adjustment of the posture sequentially. After CMM measurement, the radius of curvature, conic constant, decenter and tilt, etc. will be calculated. According to these results, the posture of the mirror will be adjusted to reduce the tilt by the designed MGSE within 0.02 degrees and the distance deviation from the best fitted profile of mirror to main plate shall be less than 0.01 mm. After that, EC 2216 adhesive is used to bond mirror and iso-static mount. During iso-static mount bonding process, CMM is selected to monitor the relative position deviation of the iso-static mount until the adhesive completely cured. After that, the wave front sensors and strain gauges are used to monitor the strain variation while the iso-static mount mounted in the main plate with the screws by the torque wrench. This step is to prevent deformation of the mirror caused from force of the iso-static mount during the mounting process. In the end, the interferometer is used for the optical performance test with +1G and -1G to check the alignment and bonding technique is well or not.

Cryogenic optical systems have a good capability and sensitivity in IR detection for its low thermal radiation and background noise. In the past, most of the cryogenic optical systems were reflective. It is very difficult to design refractive cryogenic optical systems because there is lack of cryogenic, infrared refractive index data. In order to make the refractive optical systems designing at cryogenic temperature possible, a cryogenic refractometer is very necessary. In this paper, a new cryogenic refractometer is described. It is obvious that this new refractometer should be integrated designed of structure, thermal and optical analysis. Based on the previous research, the integrated structure, thermal and optical analysis procedure is established. The cooling process of sample prism and acquired the temperature field of the sample prism and sample chamber are simulated. According to the results of FEA, 3 changes might happen during the cooling: the optical surface shape change of sample prism, the rigid-body movements of sample chamber, and the stress birefringence of sample prism. The changed optical surface can be fitted by a 36-terms Zernike polynomials, then the wavefront aberration of cooled sample prism can be estimated. It may cause the stress birefringence in the sample prism during its cooling, so it is very essential to estimate the change of refractive index which is due to the thermal stress. According to the final results of the analysis, the refractometer can be optimized.

An approach using micro lens arrays to confine the cone angle of light source in a solar simulator has been proposed to verify the Fresnel lens in a high concentration photovoltaic (HCPV) system. Compared with other three prior arts by the computer simulation, the proposed method had the characteristics of the better approximation to the direct normal insolation and the low cost. Also, to ensure the erection of the evaluation system, the tolerance of lens alignment has been analyzed. The results showed that to maintain at least the 50% of the maximum luminous flux incident on the solar cell, the transverse and longitudinal tolerances of ±1.4 mm and ±4 mm, respectively, were required.