This paper discusses the optical and opto-mechanical design of a new laser head developed at Polaroid for printing Helios binary film for printing high quality medical hard copy images. The head is part of an external drum printer for 14' X 17' film. The pixel size is 84 X 84 μm, produced by four lasers, with the smallest printable spot 3 X 6 micrometer, to produce 4096 gray levels. Two pixels side-by-side are simultaneously printed. The head has eight independent 840 nm diode lasers manufactured by Polaroid. Each laser emits up to 1.1 W over an emission length of about 100 μm, with a particularly uniform nearfield irradiance. The lasers are microlensed to equalize the divergences in the two principal meridians. Each packaged laser is aligned in a field-replaceable illuminator whose output beam, focused at infinity, is bore-sighted in a mechanical cylinder. The illuminators are arranged roughly radially. Eight lenses image the laser nearfields on a multi-facet mirror produced by diamond machining. The mirror facets truncate the beams to give the desired pixel shapes and separations. A reducing afocal relay images the mirror onto the film. The final element is a molded aspheric lens, mounted in an actuator to maintain focus on the film. The focusing unit also comprises a triangulation-based focus sensor. The alignment procedures and fixtures were devised concurrently with the head for manufacturing simplicity. The main physical structure is a casting, into which reference surfaces are machined. All optical subassemblies are attached to this casting, with a mixture of optical alignment and self-location. Semi-kinematic cylinder-in-V methodology is utilized. The active alignment steps are done in a sequence that tends to reduce errors from previous steps.

Polaroid's Optical Engineering Department has developed an autofocus module designed for use with Polaroid's multi-laser print head. The print head and focus module are now being manufactured and sold as part of a high-quality laser printer for 14' X 17' medical diagnostic images. The focus module is mated and aligned to a cylinder that is clamped into a V on the print head to utilize the semi-kinematic methodology of the print head. The printer clamps the film onto an external drum that is spun at 3300 RPM. While being spun, the profile of the film is 350 μm peak to valley. The print head's focus tolerance is ± 5μm, which is a consequence of using binary film, laser diodes, and the required gray scale. A moving objective lens that tracks the film based on real-time focus information is needed. Polaroid has developed a new focus sensor and assembly process that is economical, reliable and simple. The new sensor can be assembled in 15 minutes and replaces a more complicated design.

A glass-plastic hybrid optical system was designed and built for a direct view helmet-mounted display. This eyepiece incorporates a glass element, two aspheric plastic elements, and an imbedded diffractive surface to achieve high optical performance while reducing cost and weight. The 30 degree FOV design outperforms a previous all-glass design. The resolution requirement is driven by a 24-micron pixel Active Matrix Electroluminescent (AMEL) image source. Several design forms were considered, and the final design was chosen to facilitate manufacturing. Proof of principle units were fabricated using diamond-turned PMMA lenses. Test data are included which compare the diamond-turned and injection molded lenses. Fabrication and alignment tolerances, metrology and manufacturing issues are discussed, and both predicted and measured performance data are presented.

Obtaining omnidirectional visual information for a study of mobile robots is important for understanding robot positioning. Usually, such vision systems use a fish-eye lens or a reflecting mirror (conical, spherical or hyperboloidal). A conventional system has a problem in that an unnecessary visual field occupies most of the image. The conventional one also has a problem where the camera image is blurred due to the physical property of the mirror and a clear image cannot be obtained, especially in a dark environment. In order to overcome these difficulties, we propose an omnidirectional vision system using two mirrors with a contrived curvature for obtaining a panoramic image. The vision system consists of two axisymmetric mirrors (like a reflecting telescope) and a CCD camera. Incident rays from 360 degree surroundings are reflected twice by a primary mirror and a secondary mirror, then enter the CCD camera. A theoretical consideration is made to estimate the degree of aberration for the reflecting optical system and it uses two mirrors with arbitrary curvatures. The design method is developed to minimize the aberration of the image after the reflections of the two mirrors. The vision system can realize a clear omnidirectional panoramic image with minimum blur. The optical characteristics of the design are evaluated and the results show the effectiveness of the proposed vision system.

The results obtained in the realization of 3X magnifier hybrid optical designs for NV goggles are presented. The refractive indices of the used optical plastic materials are analyzed. A dispersive formula for IR region indices computing is used. Two eyepiece all-plastic configurations are achieved. The optical performance of the designed systems are discussed. Some updated plastic-glass optical schemes are illustrated.

A real-time three-dimensional (3-D) pickup and display setup called a Real-time IP system is proposed. In this system, erected real images of an object are formed by a GRIN lens array as element images, and are directly shot by a television camera. The video signal of a group of element images is transmitted to display device that combines a liquid crystal panel display and a convex micro-lens array, producing a color 3-D image in real-time. Full-color and autostereoscopic 3-D images with full-parallax can be observed. We confirmed the possibility of the 3-D television system.

The double expansion of wavefront deformation in Zernike polynomials over the pupil and the field-of-view is a promising approach for lens design, testing, and alignment. Conventional wavefront representation in Zernike polynomial expansion from the pupil coordinates makes it very cumbersome to consider the optical system condition over the field-of- view. Evaluating the properties of symmetry of centered and perturbed systems can provide a compact representation of wavefront deformation over the field-of-view. Even for complicated optical systems such as lithography objectives, 8 to 12 global coefficients can provide a comprehensive system description. Coefficients for centered and perturbed systems are independent.

The use of relatively simple functional form optical surface profiles has, for many years, been the standard way in which optical systems have been designed. A spherical surface profile first order design may have some or all of its spherical surface profiles changed to conic and/or polynomial aspheric profiles during the optimization process in order to add needed degrees of freedom to the design. Traditionally, surface profiles have either been picked for their functional simplicity (spheres, conics and/or polynomial aspherics) or they have been custom derived to fit a specific optical geometry. This paper takes a somewhat different design approach for systems in which "standard" optical surface profiles do not yield the required optical performance and for which custom surface profiles, based on optical system geometry, cannot easily be derived. The approach starts with a "best" design based upon spherical, conic and/or aspheric surface profiles. A non-specific functional form surface profile is then added to the standard surface profile. The retention of the 'standard' surface profile maintains a numerical legacy to the starting point design while a non- specific functional form surface profile is added to and reshapes the surface. The resultant more general surface profile yields a design which may more closely meet the system optical performance requirements. This design approach will be demonstrated with an optical design example.

A common approach used in the design of many optical systems includes the use of "standard" spherical, conic and/or polynomial aspheric surface profiles during the optimization process. Many times, the use of these "standard" surface profiles yields optical systems which either meet or exceed the optical system performance requirements. There are other optical systems, however, which cannot be optimized to their required performance levels using these "standard" optical surfaces. This paper will examine one such case and show how a new type of optical surface profile can be derived which will yield "perfect" optical performance. The derived surface equations will be coded into a user-defined surface in the CODE V optical design program, a verification ray trace will be performed and the explicit surface profile will be displayed. This technique will suggest that there may be other geometries for which surface shapes may be derived in order to solve specific optical problems.

Diamond-turning as a manufacturing method for infrared optics opens new possibilities for solving packaging problems. Optical surfaces and mechanical mounting features may be related to one another to reduce design complexity, tolerance accumulation, and cost.

Curvature sensing is an intensity-based technique for wavefront reconstruction using two defocused images located on the opposite sides of the focal plane. It requires either one detector placed at two consecutive axial locations or a dual path with a pair of detectors from which the sensor signal is obtained. The method yields a sensitivity comparable to that of the Hartmann test in the adjustment and evaluation of ground-based optical telescopes. We introduce the analytical framework underlying the function of a curvature sensor which operates from a single defocused image. A series of twin images is computed from the propagation law of the mutual intensity along the optical axis. The polynomial decomposition of the wavefront allows retrieval of Zernike coefficients by means of the standard least-squares algorithm. The paper concludes with a review of image sampling requirements and a discussion on the signal-to-noise ratio.

Steward Observatory is building a deformable f/15 secondary mirror for the 6.5 m Multiple Mirror Telescope conversion that will compensate for atmospheric turbulence. A potential difficulty of an adaptive secondary mirror is the ability to verify the commanded mirror shapes of a large convex deformable surface. A new optical design is presented to test the deformable mirror's closed loop control system by optically projecting an artificial star to simulate starlight in the actual telescope. An optical fiber fed interferometer has been incorporated into the design to measure the deformable mirror's ability to compensate for atmospheric turbulence by measuring the wavefront through an atmospheric turbulence generator. The test system has been designed to verify the control system by fitting into both a laboratory test structure as well as the telescope support structure itself. The optical design relies on two wavelength computer generated holograms used to remove spherical aberration as well as aid in the alignment of the test system optics by projecting alignment patterns.

Manufacturing test structures of microsystems and microcomponents is very expensive in terms of time and materials. In conventional design processes, this limits the number of design variants to be considered. For this reason, computer-supported design techniques are becoming more and more important in microsystems technology. The article describes a micro-optical structure as an example demonstrating the factors which disturb the operation of a micro-optical module, and derives a theoretical description of the system under consideration which allows the system parameters to be optimized with respect to the disturbing influences by means of an evolutionary search method.

The results of obtaining and investigations coated optics in deep ultra violet (UV) at 193 nm are considered. For successful using in excimer lasers and medical systems the separate optical elements must provide either a good transmission for laser irradiation or enough high reflection. This can be achieved by anti-reflective (AR) or high- reflective (HR) interference coatings. Numerical design and obtaining of UV dielectric coatings are strongly influenced by the material properties in this wavelength region, that differ from those in visible and near infrared. The peculiarities for thin films in this region are: a limiting factor of the evaporation materials, homogeneous along the surface of optics, and high laser strength. The interaction between excimer laser photons and optical coatings can be determined as two combined process of high repetition rates and high energy densities. These processes influence both on substrate and on film. In this connection the investigations of optical properties of oxides (Al₂O₃, SiO₂) and fluoride (MgF2) films are observed. Besides some new aspects in investigation of pure substrates are obtained. All films were produced by electron-beam evaporation and ion-beam influence was analyzed as variation of optical absorption and laser damage threshold (LDT) of coated optics.

We raised a novel method to test radial run-out of optical disc. The method measures run-out by track-across signal when optical head keeps focusing on rotating disc and stops in radial direction. The track-across signal can be picked up from commercial disc drive. Then the distance of passed tracks is calibrated by linear gratings. The advantages of this method are low-cost and high accuracy.

Recent decades blue-green laser submarine communication (LSC) system has been developed as an important inter-medium transmission method for submarine communication. But the developed LSC system has only one-way communication from an air platform to a submerged platform. In this paper, we introduce a novel optical system, i.e. underwater modulable hollow retro-reflector (UMHRR) in ocean, for a new possible SLC system in future. The new system may establish a round optical link channel and allows for two-way communication from air to submarine and back. Also, we firstly develop an UMHRR for a potential application such as an underwater optical beacon.

Compact small monolithic cemented laser gyroscope with cemented monolithic high stable and high precision laser wedge micro interferometer has described. To ensure high stability (and thus, high precision and high accuracy) against misalignment and against deformations errors, monolithic microinterferometer with wedge prism cemented with CCD and semitransparent mirror made on a long side of wedge monolithic microinterferometer prism. And for this aims monolithic wedge microinterferometer is cemented in long side (semitransparent mirror) with a ring laser with the high stability. For high stability wedge microinterferometer with ring laser is made of zero expansion material, and in the ring laser spherical mirror and a plane mirror made on different sides of a monolith zero expansion material. Laser gyroscopes are simple, low cost and easily can be manufactured in quantity.

'Ab initio' design of a Cooke triplet usually necessitates a heuristic preselection of optical glasses for the three lens elements. Though some rules of thumb are available for specific cases in general, this is a tricky problem, and often one has to take recourse to a trial and error approach. We propose to tackle the complex problem of design of a Cooke triplet lens with prespecified aberration targets by reducing it to relatively simpler problems of design of individual components with required amounts of primary spherical aberration, central coma and longitudinal chromatic aberration. This reduction is implemented by a global optimization technique. Our method of global optimization is developed along the lines of the well-known method of simulated annealing. Some new features like constrained random walk have been incorporated for facilitating the solution of our problem. A followup procedure also based on global optimization seeks singlet lenses for the individual components. In case of nonavailability of suitable singlet for a component, one seeks to satisfy requirements of that particular component by using a suitable doublet lens. Indeed, the approach provides a systematic method for the development of triplet derivatives as and when required.

The design of the planar multi-layer switches, obtained by the Euler path through the switch intersection graph (IG), is discussed with regard to the (1) minimum crossings (2) minimum number of stages (NS) and (3) minimum crosstalk (of 1st order). The main part is devoted to crossing waveguides between the switching matrix (equivalent parallel waveguides, PWs) and the path-selection switches (PS - SWs).

A control technology testbed for the Ultra-Lightweight Imaging Technology Experiment (UltraLITE) program at the U.S. Air Force Research Laboratory is described. The goal of the testbed is to demonstrate technology readiness for controlling boom-mounted, rigid body mirror positioning while rejecting spacecraft disturbances and overshoot oscillations due to rigid body retargeting. This paper describes the three main phases of the testbed: concept definition, mirror initial simulator bench top experiments and the boom/mirror control experiments. Emphasis on recent results from the bench top and boom/mirror experiment will be presented. To date, designs of several different types of disturbance rejection controllers for meeting the nanometer positioning requirements have been shown for the mirror inertial simulator mounted to an optical bench. Control methodologies for designing these systems included ARMA and LQG/LQR methods augmented with control logic for coarse control correction also included. Brief explanations of the experiment's traceability to the UltraLITE space imager concept and an explanation of the boom/mirror hardware setup are also included.

This paper presents the analytical methodology and initial numerical simulation results for autonomous neural control of the Ultra-Lightweight Imaging Technology Experiment (UltraLITE) Phase I test article. The UltraLITE Phase I test article is a precision deployable structure currently under development at the United States Air Force Research Laboratory (AFRL). Its purpose is to examine control and hardware integration issues related to large deployable sparse optical array spacecraft systems. In this paper, a multi-stage control architecture is examined which incorporates artificial neural networks for model inversion tracking control. The emphasis in the control design approach is to exploit the known nonlinear dynamics of the system in the synthesis of a model inversion tracking controller and to augment the nonlinear controller with an adaptive neuro-controller to accommodate for changing dynamics, failures, and model uncertainties.

A spatio-temporal filter (STF) based active vibration suppression technique is presented. The STF approach is intended for use for stability and jitter compensation for the UltraLITE Precision Deployable Experiment -- a ground demonstration of a sparse array, deployable, large aperture, optical space telescope concept. This technique is well suited for control of complex, real-world structures because it requires little model information, autonomously accommodates sensor and actuator failures, is computationally efficient and the controller is easily updated to account for time varying system dynamics. An overview of the STF approach is given and experimental active vibration suppression results obtained on the Mirror Mass Simulator testbed at AFRL, Kirtland AFB are presented.

While significant theoretical and experimental progress has been made in the development of neural network-based systems for the autonomous identification and control of space platforms, there remain important unresolved issues associated with the reliable prediction of convergence speed and the avoidance of inordinately slow convergence. To speed convergence of neural identifiers, we introduce the preprocessing of identifier inputs using Principal Component Analysis (PCA) algorithms. Which automatically transform the neural identifier's external inputs so as to make the correlation matrix identity, resulting in enormous improvements in the convergence speed of the neural identifier. From a study of several such algorithms, we developed a new PCA approach which exhibits excellent convergence properties, insensitivity to noise and reliable accuracy.

The need arises in adaptive closed-loop control to identify an efficient dynamic model of the system in real-time. It is well known that a general nu-input, ny-output, strictly proper system of order n possesses n(nu + ny) independent parameters. However, most on-line identification techniques identify many more parameters than these. For example, in an ARMA realization the number of parameters identified is at least n(1 + nu (DOT) ny), which is of third order in the size parameters. This paper presents a means of identifying only the minimum number of parameters, while avoiding non- convex optimization that results in local minima.

Hartmann sensors and shearing interferometers have dynamic range limitations which bound the strength of the aberration which can be sensed. The largest aberration which can be reliably sensed in a Hartmann sensor must have a local gradient small enough so that the spot formed by each lenslet is confined to the area behind the lenslet -- if the local gradient is larger, spots appear under nearby lenslets, causing a form of cross talk between the wave front sensor channels. Similarly, the effectiveness of shearing interferometer-based aberration sensing can be reduced by strong phase gradients which cause unresolved 2π phase jumps in the measured fringe pattern. In this paper we describe a wave front reconstruction algorithm which processes the whole image measured by either a Hartmann sensor or a shearing interferometer, and a conventional image formed using the incident aberration. We show that this algorithm can accurately estimate aberrations for cases where the aberration is strong enough to cause many of the images formed by individual Hartmann sensor lenslets to fall outside the local region of the Hartmann sensor detector plane defined by the edges of a lenslet.

A detailed simulation of a white light interferometer system for measuring nanometer scale structural motion is presented. Two operational methods are studied: low bandwidth, low resolution centroid tracking of the structure motion, and fine resolution, high bandwidth fringe tracking. A Michelson interferometer is modeled with one optical path containing a target mirror attached to the structure, and the second path containing a voice coil actuated reference mirror for path length difference control. Simulation results reveal a 3 nanometer RMS error for a 1 micron, 100 Hz structure motion during fringe tracking. This system is being developed at the Air Force Research Laboratory, Space Vehicles Directorate, under the UltraLITE program as part of an imaging spacecraft brassboard demonstration that requires 12 nanometer RMS absolute piston control.

A system is presented for sensing nanometer scale structural disturbances using white light interferometry in conjunction with a tracking controller. A Michelson interferometer is established using a fiber-coupled white light source, a beamsplitter cube, an actuated reference mirror, and a retroreflector attached to the structure of interest. Structural motion is determined by actively tracking the zeroth order white light interference fringe. A multimode controller architecture enables location of the white light fringe packet, coarse tracking of the packet by modulation of the actuated mirror, and fine tracking by locking onto the slope of the zeroth order fringe. Resolution and bandwidth of the measurement system is increased at each successive mode. Experimental results of the system prototype are presented. Applications include position control of optical elements in segmented aperture imaging systems such as the Next Generation Space Telescope and the USAF Research Lab UltraLITE space imager.

A new approach to lightweighting large optics using the abrasive waterjet (AWJ) milling process has been developed and has demonstrated that significant weight reductions in glass face sheets can be achieved. The AWJ glass milling process has been developed to offer a safe and low cost machining alternative over conventional methods that are considered a high risk machining process. The lightweighting approach has been oriented towards precise controlled depth milling of isogrid pattern pockets in the back side of optic face sheets. The AWJ milling process has been successfully applied to lightweighting a wide range of materials; such as ULE, Zerodur, Fused Silica, Fused Quartz, and Pyrex, with part sizes ranging from 70 mm (3 inches) in diameter to in excess of 2 meters (80 inches) in diameter.

The micro-adjusting structure of servo mirror used for laser- beam aiming in this paper is expounded. The main character of the structure is described. The structure is analyzed for mechanics, and its rigidity under different mounting directions. Through a deal of calculation, the deformation of elastic supporting structure is also analyzed. The main influencing factors of rigid structure are given out.

The optical support boom and related facilities for the Ultra- Lightweight Imaging Technology Experiment (UltraLITE) program at the U.S. Air Force Research Laboratory are described in this paper as well as the implementation of a local feedback loop to control the boom's first bending mode. The primary goal of the efforts described in this paper are to provide a relatively quiet vibration environment for optical active control experiments to be performed on the deployable optical support boom. The optical active control experiments to date are described in a companion paper.

Thin membranes with curvature are investigated as mirror substrates for use in large optical telescopes. These films are mounted on an optically flat circular ring and stretched over a smaller optically flat circular ring where pressure or vacuum is applied to create the doubly curved surface as shown in figure 1. The films may vary in thickness from 20 to 200 microns. This particular experiment examines an aluminum coated 125 micron thick homogeneous, planar, isotropic membrane with a clear aperture of 28 centimeters. The nature of a flexible membrane implies that the surface curvature will result in an assorted array of gross surface figure issues associated with deterministic shape limits, probabilistic imperfections, nonlinear constitutive effects, and long-time- dependent effects. This report will focus on the empirical deterministic shape limits of a doubly curved membrane. Theoretical work on thin films inflated or evacuated into a doubly curved surface has a long history, and remains an active area of research. A number of articles [1,2,3,4,7] include summaries of this history, and offer insight on the deterministic membrane shapes.

Recent developments in the design and fabrication of very light-weight all-composite mirrors have made possible extremely well balanced, thermally stable, structures which distort very little when cooled. One such mirror is the Composite Optics, Incorporated all-composite mirror, M4, which has a 45.7 cm diameter and 3 cm thickness and a spherical surface of radius-of-curvature 2.92 meters. Relative figure measurements of this mirror were made with the Steward Observatory Light Weight Mirror Low Temperature Test Chamber over a temperature range from 20 C to -60 C using a 10.6 μm interferometer. The measurements show a remarkably small increase in the rms figure departure from a spherical surface of fixed radius-of-curvature of 0.27 μm over the 80 C temperature change. The effective coefficient of thermal expansion over this temperature range derived from the focus change is 0.66 x 10^-6/C, close to that of fused silica.