Several of NASA's future space telescopes project teams have chosen or are considering segmented primary mirrors as a part of their architecture. The James Webb Space Telescope (JWST) design employs a 6.5-meter conic primary mirror constructed of 18 hexagonal segments, where each hex is one of three off-axis surface profiles corresponding to its radial distance to the parent mirror axis. Other future mission concepts such as SAFIR (Single Aperture Far-Infra Red) and SUVO (Space Ultra Violet Optical telescope) are considering even larger segmented primary mirrors. The goal of the Spherical Primary Optical Telescope (SPOT) project discussed in this paper is to investigate the option of a spherical primary mirror for such future large aperture NASA missions. Ground-based telescopes such as the Hobby-Eberly have realized this design option, and the current baseline design for ESO's OWL project incorporates a 100-meter segmented spherical primary mirror. While the benefits of fabricating large numbers of identical spherical surface segments are obvious, the optical design for the telescope becomes more complex in order to correct the significant aberration resulting from a spherical primary surface. This paper briefly surveys design approaches of spherical primary telescopes. Image based performance comparisons are made, and examples are presented.

Innovative optical designs are needed to create the space sensor systems of the future. The NASA mission development process has created several very challenging design and engineering problems. Three of these are discussed: The SAFIR is a 15 to 25 meter clear aperture telescope cooled to 4 degrees Kelvin, with spectrographs and imaging systems cooled to 1 degree Kelvin. The Terrestrial Planet Finder (TPF) will detect and characterize planets in orbit about other stars, The Stellar Interferometer (SI) will image across the surfaces of distant stars. Issues related to optical design & engineering and image quality will be discussed. This paper reviews the optical systems and engineering needs for next generation astrophysics missions.

Future large-aperture optical space systems will need to use lightweight materials that meet stringent requirements, and that reduce program and launch costs. Lightweight optical systems produced quickly and cost-effectively, and the resultant lighter payloads, can reduce these costs. Mirrors for future systems have areal density goals of less than 5 kg/m² and will need to use new materials1. A promising one is silicon carbide (SiC) because of its physical and mechanical properties. These enable the production of low areal density, high quality mirrors, as well as lightweight athermal telescope structures. Athermal structures are desirable because they simplify designs and reduce tolerance requirements to maintain performance during on-orbit temperature changes. The use of SiC to make mirrors and structures is in the developmental stage and has limited space heritage. To ensure the use of this material in space applications, qualification and system performance in the space environment must be addressed. This paper provides an overview of SiC, along with recommendations to further the development of SiC into a mature technology that can be successfully integrated into future large-aperture optical space programs.

We present results on the final optical design, flexure tolerances and stray light analysis of the UBC Universal Beam Combiner (UBC) of the Large Binocular Telescope Interferometer (LBTI). It is expected to produce 40x60 arcsecond field with 20 milliarcsecond resolution in 2.2micron region for Fizeau Imaging.

The James Webb Space Telescope (JWST) is a large space based astronomical telescope that will operate at cryogenic temperatures, utilizing a segmented primary mirror with active control. To achieve the science goals for JWST, the design requires a large collecting aperture and stable PSF to detect distant faint sources, and a large field of view to accommodate multiple large field of view instruments for efficient surveys. This presentation will give an overview of the mission optical requirements and optical architecture. It will describe the telescope design, highlight some of the features of the baseline telescope, and discuss the nominal performance. In addition, it will provide an overview of the wavefront sensing and control process, and describe some of the special optical analysis considerations necessary in a system needing remote, on-orbit alignment.

The "conventional" procedure in evaluating the image degradation caused by deformed optical surfaces uses only the local Z-component of the optical surface's nodal displacement vector along with the nominal X and Y-coordinates directly from a finite-element model (FEM) to evaluate a Zernike polynomial. The surface's decenter is handled separately. This method may produce significant errors if thermal loads and complex load combinations are considered. An alternative vector approach, which overcomes this problem in a single step, is presented.

Telescope performance is often limited by aberrations, and/or fabrication and alignment errors. Additionally, image formation in large space-based systems is sensitive to changes in physical form parameters such as temperature-related deformations, mirror structure, piston position and detector alignment. Changes in these parameters significantly degrade image quality and often limit the performance of the system. A fundamental new technology called Wavefront Coding has been successfully demonstrated via simulations for large space-based imaging systems that promise to surpass the performance attained by traditional optical designs. Wavefront Coding uses specialized aspheric optics and signal processing of the detected image to correct defocus-like aberrations thereby enabling a new paradigm in aberration balancing for telescope systems. Wavefront Coding can provide dramatic new mission capabilities by allowing space-based imaging systems that are simpler, lighter, and cheaper, while also providing high quality imagery in dynamic environments that are difficult or impossible to image in with traditional imaging systems. As an example two systems are presented that allow the telescope to repoint the boresight through the actuation of the primary segments or through the use of a scan mirror. Traditional systems with the same goal of repointing the boresight historically have not been feasible due to either the increased error space or due to constraints on system cost and complexity.

Phase diversity imaging is an established technique for deriving optical phase information from measurements of intensity. Knowledge of the optical phase can then be used to provide real time feedback control to adaptive optics or to perform post-detection image restoration. The work presented in this paper concerns the use of phase diversity to improve image restoration for aberrated optical systems. All previous implementations of phase diversity imaging of which the author is aware use defocus to introduce phase diversity. Defocus is rotationally symmetric with respect to the optical axis (no q dependence) and has an approximately quadratic dependence (ρ^2) on the radial coordinate in the exit pupil plane. Because of this rotational symmetry, defocus diversity is effective in improving the quality of image restorations only for even-order aberrations such as spherical (ρ⁴) and astigmatism (ρ²•cos²θ). However, simple defocus diversity fails to improve the quality of image restorations for odd-order aberrations such as coma (ρ³•cosθ). This paper explores the use of non-quadratic and rotationally non-symmetric phase diversity versus standard defocus diversity. Simulated image restorations are presented for a hypothetical system that would use an adaptive optic to introduce generalized phase diversity to remediate the impact of residual aberrations.

We describe a new method of testing optical surfaces having a very large radius of curvature. The method combines a Fizeau interferometer with a set of specially designed zoom lenses. The zoom lenses make the test setup compact, convenient and flexible in testing optical surfaces having a very large radius of curvature. We review the design of the zoom lenses used for this purpose, and describe their performance, showing that reasonably good reference beams can be provided by these lenses to test optical surfaces having a large and variable range of radii.

This paper discusses the design of a 310 degree fisheye lens. Particular attention is paid to color correction and lens edge overlap. Other issues in the design of fisheye lenses are addressed such as the distortion/mapping, illumination, and overall aberration correction. The general format and structure of fisheye lenses are discussed including a brief history of these fascinating lenses.

Angle-to-area converters are a key topic of illumination design, and much work has been done in this area over the last 30 years. However, relatively little work exists in the literature in which these converters have been designed using optimization techniques. The present work takes a fresh look at some angle-to-area conversion problems using optimized, circularly and non-circularly symmetric surfaces.

Recently the author described a method that gave the complete solution set for four-mirror anastigmats in which all the mirrors were spherical. Even though a large variety of such systems were shown to exist, most of these were not practical due to large central obstructions. The author has now modified his previous approach by setting up "partial" systems with good first order characteristics and adding the minimum number of aspheres necessary to give anastigmatic correction. In this way, surveys of useful four-mirror anastigmats with one, two or three-mirrors kept strictly spherical can be carried out.

We have developed a novel stacked silicon-based microoptical system, which is optical-on-axis and transmissible in both visible and infrared ranges. By using the new microoptical system techniques, we fabricated a miniaturized optical pickup head module. This optical pickup head consisted of a 650nm laser diode, a 45 degrees silicon reflector, a grating, a holographic optical element, and some aspherical Fresnel lenses. These optical phase elements fabricated on a SiNx membrane were free-standing on Si chips. Each element was then stacked by chip bonding. We could obtain a circular focusing spot on the optical disc as small as 3.1um.

We present a microscope imaging optics system that is suitable for simultaneously detecting two species of electrically trapped atomic ions for quantum information processing. The proposed 10x objective features all-spherical surfaces in a catadioptric modification of the Schwarzschild two-mirror configuration and is achromatic at 313 and 280 nm, the two wavelengths of the laser-induced fluorescence from ⁹Be⁺ and ²⁴Mg⁺. To correct for aberrations from the fused-silica vacuum window, we use a zero-power doublet made of a positive calcium fluoride and a negative fused-silica meniscus to form an air-gapped Steinheil doublet facing the object. As a result, diffraction limited images are obtained for both wavelengths at a numerical aperture (NA) of 0.5 and a field of view (FOV) of 0.1 mm in diameter. The long working distance (> focal length) of this objective allows imaging of the ions through the vacuum window.

Glass selection tends to be both a science and an art. It is the intent of this paper to remove the "mystique" surrounding glass selection, primarily based on the chromatic properties of the glass, and to show via careful parametric analyses how we can optimally select glasses for lenses of different f/numbers, spectral bands, and performance requirements. The important roles of refractive index and Abbe number as well as partial dispersion will be considered. Using the SCHOTT glass map, six separate and identifiable regions along with glasses within each region will be discussed. The goal for this paper is to make glass selection easier to understand.

Dispersive filtering has been shown to be an effective means to prevent color aliasing in digital images from sensors supplied with a mosaic filter pattern. Sensors with mosaic color filters typically measure only a portion of the color information for each pixel. To record full color information requires the information from several laterally displaced pixels. Dispersive filtering introduces a similar lateral displacement in the optical image. When sensed with the corresponding laterally displaced pixels, a color registered data set is produced. Limitations of available optical materials, and color sensors restrict the exact registration to an approximation. This paper quantifies the residual errors of dispersively registered images for two current mosaic sensor types.

We present in this paper the development of novel mid-to-far IR filters that are based on porous silicon structures. The diameters of the pores in such filters are by orders of magnitude less than the central wavelength of the transmission band, leading to effective averaging of the porous structure by the light waves. Such filters have a number of important advantages over multilayer interference filters. Since the filters are made from a single material by means of an electrochemical etching process (rather than through deposition), these filters do not exhibit delamination problems and are well suited for operation at extreme temperatures (for example, in the environment of space). Our fabrication technique permits the fabrication of filters up to 200 mm (8 inches) in diameter, suitable for any wavelength from below 1.1 μm to more than 45 μm. The results of experimental testing of such filters are shown to prove the main predictions.

A new type of fiber optical liquid refractometer based on total-internal reflection heterodyne interferometry (TIRHI) is proposed. The phase shift difference due to the TIR effects between the P and S-polarizations is measured using heterodyne interferometry with a D-type fiber sensor. Substituting the phase shift difference into Fresnel's equations, the refractive index can be calculated. It has some merits, such as, high sensitivity and stability, small size and real-time measurement.

Laser scanning displays offer the possibility of creating bright, high-resolution images from compact projection devices. The requirements of the optical systems that produce quality images using scanned laser illumination differ significantly from traditional incoherent projection systems. In scanning systems, the laser beam size and quality determines the resolution of the scanned line. The geometrical orientation of the scanning mirrors has a significant impact on distortions that appear over the entire scanned image. In addition to the influence of Gaussian beam characteristics and geometrical factors on scanned image quality and system design, we also discuss optical, mechanical and electronic features of MEMS based scanning systems that keep manufacturing costs low.

Traditional projection engine designs are mostly based on propagation of light through standard components, such as, dichroic filters, lenses, polarization beam splitters, prisms, etc. These components are usually held individually using optical mounts and assembled together on an optical bench such that all the components are aligned properly. Even in high volume production environment, it tends to be tedious and expensive. With the advancement of light pipe based illumination system, e.g. the Wavien patented dual paraboloid reflector system, and light-pipe based polarization recovery system, it would be advantage to design a light-pipe based projection engine for a complete light-pipe based system for low cost and space saving applications. Except the projection lens, a totally light-pipe based projection engine is described. It consists of an etendue efficiency illumination system using the dual paraboloid reflector system with a lensed tapered light pipe at the output. The output is then directed into a light-pipe based polarization recovery system such that the output is polarized. The polarized light is then separated into its individual RGB colors, and is directed into the corresponding HTPS imager chips separately by the use of light pipes, prism, and beam splitters. The outputs from the imager chips are then recombined by an X-cube and projected onto the screen. A design has also been made for LCOS imagers. The folding and unfolding properties of the light pipe are used in this case resulting in a more compact projection engine. This light-pipe based system uses low cost optical components and takes up much less space than the traditional projection system.

Optical system modeling is interdisciplinary by its very nature. Optics, thermal engineering, structural engineering, control systems, electrical engineering, and data analysis are among the disciplines required to perform such modeling. Each discipline tends to have various software tools at its disposal to perform the required design and analysis but the software tools have had only limited ability for interdisciplinary use. Optical design software can form the core for optical systems modeling in many instances but its capabilities must be extended, or it needs to be used in a non-traditional way, depending on the problem at hand. We have used optical design software to assist in or form the basis for solving a number of interdisciplinary optical systems modeling problems. As an example, we present our method of dynamic optical ray tracing here and show its application. We also mention an example of linking optical design software to external code to solve optical systems modeling problems. Although these modeling efforts were successful, they illustrate the associated difficulty and need for integrated software modeling tools.

Simplex optimization is a powerful method of finding minima in noisy merit function spaces, such as those for illumination. The standard simplex routine and a modified one developed by the author are applied to three lens design problems found in the literature: singlet, cemented doublet, and triplet. The starting conditions of the size of the simplex and the location in merit function space are investigated. It is found that the modified simplex routine provides better results than the standard one as the solution converges to the optimal solution, which is called the "end game". The standard simplex tends to provide better results than the modified one when operating in the "start game". The simplex results are compared to those from a commercially available lens design code. In most circumstances the commercially available code provides better performance in both iterations to convergence and quality of the result. The results presented herein provide confirmation that the modified simplex algorithm is a viable means of optimization for noisy merit function determination when in the neighborhood of local optima.

Off-axis illumination optics has being used in microlithography for projection printing since 90th. It increases resolution and depths of focus for certain layout patterns and design styles. First annular, then quadrupole, and lately dipole source shapes are getting deployed. The source shape can be formed by hard stop apertures or by diffractive optical elements (DOE). The former is advantageous because it preserves light energy on the way from a laser source to the mask (object). In addition, DOEs can form very complex source shapes, with smooth distribution of light across the aperture. This enables source tuning to print certain layout features with a high resolution. Though printing hardware is ready for complex shapes to be used, optimization methods are not well developed. In this study we first review existing source optimization methods. Lack of rigorous formulations motivates discussion of the optimization objectives and constraints. We stress importance of using weighted and so-called Sobolev norms. Second, we state the main optimization problem as a set of the optimization objectives in a form of functional norm integrals to maximize image fidelity, system throughput, and source smoothness. We show how to reduce this to a non-negative least square (NNLS) problem, which is solved by standard numerical methods. Third, we analyze solutions for important practical cases: alternating phase-shifting regular and SRAM cell. An actual DOE element was fabricated for one of the SRAM cells, which accurately reproduces a very complex off-axis illuminator light distribution. Finally we show how constraint optimization can be used to smooth strong off-axis quadrupole illuminations in order to achieve better image fidelity for some selected layout patterns.

Efficient calculations in optical engineering are rarely accomplished through brute force raytracing. Using techniques derived from radiometry, it is possible to perform stray light, illumination uniformity, and thermal self-emission calculations both efficiently and accurately in a small fraction of the time it would take to trace the requisite number of rays.

This paper will describe and discuss the head up display analysis routines that are used in the Thales Optics optical design software and how these have been enhanced and supplemented to meet the requirements of modern avionics specifications. Specific examples will be given illustrating methods of presenting collimation errors, binocular disparity, field of view, pupil shape and aperture definition on specific surfaces. Some of the methods of presenting collimation errors lend themselves to differential analysis making them useful for considering manufacturing tolerances.

The method of damped least squares (DLS) is probably the most widely used method in optimization of lens systems. The main obstacle in this method is the choice of weights that are applied on functions of different nature involved in the construction of a merit function. This merit function should lead to the final goal of optimizing the lens system. An alternative to DLS is the method of constrained damped least squares (CDLS). In this method functions of lens parameters are separated into two sets: (1) functions related to image quality (aberrations) that are weighted, squared, added and then minimized, and (2) all other functions, or constraints, of varied nature, that are brought to zero or negligible values and for that reason they do not require weights assigned to them. Specifically for this reason it is immaterial whether theyt are of different nature or not. Optimization in either method is carried out in successive approximations or cycles. In DLS the end point of one cycle is the beginning point of the next cycle. In CDLS there is a gap or discontinuity between these two points; its magnitude depends on the size of the residual constraint errors. If the discontinuity is too large it may adversely affect the progress of optimization. It is possible to reduce the magnitude of the discontinuity by controlling the optimization progress and then to proceed in an orderly fashion towards the final goal.

Thin-film coatings in modern optical systems as wideband AR-coatings may have >10 layers and an optical thickness of several λ. Such complex thin-films may introduce pronounced changes in transmission phases with varying angles of incidence, polarization and/or wavelength. "Polarization ray tracing" as utilized by current optical design programs models a "ray" as a "localized plane wave" hitting the air/thin-film/glass system and the transmission properties in phase and amplitude for the p- and s-components are taken into account. However, this only approximates the thin film as a pure phase object of vanishing thickness on a flat surface. Any "ray" crossing a layer of finite thickness will undergo lateral displacement and on a surface of notable curvature, this displacement will further change the direction of the refracted "ray". Both effects might become important in high NA, deep UV microscope objectives based on an air-spaced design that involves a large number of highly curved air/glass interfaces, large angles of incidence and tight tolerances. This paper shows how the equivalent lateral ray displacement and bending can be calculated from the film/glass properties and the surface curvature and how it can be incorporated into a polarization ray-tracing program. It also addresses other problems encountered in polarization ray tracing of thin films, as proper conversion from phase shifts to optical path length and how to easily "unwrap" the thin-film induced phase.

This paper presents a case study in using the CODE V optical design software to model an astronomical adaptive system end to end. Such models can be useful in predicting system performance and in garnering a better understanding of the process of adaptive correction. Described in this paper is the model itself and the custom macros that are extensively used throughout to measure the wavefront aberration; drive the adaptive system and collect the resulting data. Of special interest is the algorithm used to create the turbulence screen. The turbulence created by this sine wave summation algorithm is in keeping with Kolmogorov statistics that are commonly used to describe atmospheric turbulence at astronomical sites.

Systems which transform optical wavefronts into digital information for imagery or machine interpretation lack suitable design tools and methods. In Wavefront Coded imaging systems in particular, the signal processing and the optics must be jointly considered to achieve an optimal solution. Computational imaging systems have recently been designed at CDM Optics based on human interpretation of images and guided by machine (algorithmic) interpretations. CDM is generating an integrated design package called WFCDesign to provide for truly joint optimization of computational imaging systems where both physical and algorithmic goals can be jointly realized with a high degree of efficiency and accuracy. WFCDesign interfaces to a multitude of commercial analysis, design, signal processing, and simulation packages, enabling joint optimization using industry-standard tools. Methods for approaching the optimization problem including merit functions and optimizer issues are discussed. An example of a computational design with Wavefront Coding based on a digital algorithm's performance (as opposed to strictly optical metrics such as spot size or aberration curves) is provided. An outline and discussion of the WFCDesign package highlights the capabilities of our flexible approach and modular architecture and provides insight into the future of computational imaging design tools.

Short-arc pulsed xenon flashlamps are used as the source of optical radiation in many analytical and life science instruments. They provide useable energy from below 150nm to over 1100nm. However, the distribution of spectral energy within the arc discharge is not uniform. This non-uniformity can lead to problems when attempting to model the arc in software. This paper will look at the shape of the arc in short-arc pulsed xenon flashlamps in different spectral regions and use the data collected to generate a more complete model of the arc. Possible ways of using this information in optical modeling software will also be discussed.

Evolution strategies (ES) are appropriate for optimizing multi-variable problems in different areas of engineering. ESOP is the working environment of a feasibility study in progress, which implements an evolution strategy in optical analysis and simulation software. The implementation of a simple strategy including step width variation in a software application for optical design and analysis for illumination (TracePro, Lambda Research Corp., Littleton, MA) is described. More practical than theoretical consideration is paid to the requirements, dependencies and the user interaction of such an implementation for real world applications. The capabilities of ESOP are demonstrated by two different examples: a conical 8 times faceted reflector and a cathode tube display. Both shall distribute their energy uniformly over given target faces. The results show that substantial improvements in the uniformity of the distribution and the total energy on the target face are possible. Advantages are the stability of the algorithm and the possibility to provide an optimization tool, which is applicable to most illumination problems.

Microstructured optical fibers (MOFs) are optical fibers having a periodic air-silica cross-section. The air holes extend along the axis of the fiber for its entire length. The core of the fiber is formed by a missing hole in the periodic structure. Remarkable properties of MOFs have recently been reported. This paper presents new work in the modeling of the propagation characteristics of MOFs using the Finite Element Method (FEM) and the Galerkin Method (GM). This efficient electromagnetic simulation package provides a vectorial description of the electromagnetic fields and of the associated effective index. This information includes accurate determination of the spectral extent of the modes, cutoff properties and mode-field distributions. We show that FEM is well adapted for describing the fields at abrupt transitions of the refractive index while GM has the advantage to accurately analyze MOFs of significant complexity using only modest computational resources. This presentation will focus on the specific techniques required to determine single mode operation, dispersion properties and effective area through careful choice of the geometrical parameters of the fibers. We demonstrate that with suitable geometrical parameters, the zero dispersion wavelength can be shifted. This tool can also provide design criteria for fabricating MOFs and a corresponding map of effective area. This approach is validated by comparison with experimental results and measurements on actual MOFs fabricated at IRCOM and at Alcatel Research and Innovation Center.

In order to measure laser-produced plasma x-ray in the 1.33-2.46-nm region, an elliptical crystal spectrograph has been designed and fabricated. The potassium acid phthalate (KAP) crystal with a 2d spacing of 2.663 nm is used as the x-ray dispersive element, it is elliptically bent and glued on a rustless-steel substrate with a 0.9586 eccentricity and a 1350-mm focal distance. The spectrograph is equipped with an x-ray charge-coupled device (CCD) camera for recording the space-resolved spectrum on one port, and an x-ray streak camera for recording the time-resolved spectrum on another port. The first testing experiment was carried out on the XG-2 target chamber, the experimental results demonstrate that the spectral resolution is about 640 for this spectrograph.

A novel elliptical crystal spectrometer has been designed and manufactured to diagnose pulsed plasmas x-ray. The light path is designed according to the elliptical focusing property. The spectrometer is composed of the elliptical x-ray analyzer, the alignment devices, the vacuum system, the ports of the spectral detectors for x-ray CCD camera and x-ray streak camara, the supporting base, and the adapting flange to the target chamber. The target-shooting experiment was performed at the XG-Π and SGΠlaser facilities for testing the spectrometer. The optical system, optoelectronic machinery system, experimental results are discussed in this paper.

A four detectors polarimeter is originally invented by Azzam et. al. We have modified their idea and developed a new four detectors polarimeter of a transmission type (T-FDP) which has some advantages over the conventional one. Further modification of our T-FDP to the M-TFDP is reported. The alignment procedure of the optical system is also discussed as the application of the M-TFDP to ellipsometry.

Tunable interleaver filters are very important in DWDM applications. To be effective, it is required that the filters must possess wide passband (or stopband) width, high isolation, small channel spacing, high tuning speed an so on simultaneously. Whereas, for the small birefringence of all the natural crystals and synthesized crystals, it is quite difficult for the available birefringent interleavers to have the channel spacing smaller than 50GHz and other properties mentioned above simultaneously. This paper proposes a novel electro-optically tunable birefringent interleaver filter, which solves the problem successfully. It is based on cascaded analog birefringent structures. The filter of this configuration can achieve small channel spacing (≤50GHz), wide passband and stopband width (>1/5 period) and high isolation (<-30dB). When voltage is applied on electro-optical crystal plates in analog birefringent structures, the filter also possesses the function of high-speed (submicrosecond) center-frequency tunability simultaneously. A most efficient electro-optic configuration, which needs the lowest operating voltage and has not walk-off effect of extraordinary ray in the crystals, is proposed and analyzed. A prototypical experiment verifies the electro-optic tunability of this filter as well.

We demonstrate experimentally fabrication of optical elements with femtosecond pulses. The laser source we adopted is a low power Ti: sapphire laser oscillator, with a central wavelength of 790 nm and pulse duration of 100 fs. Positive-photoresist-film-coated glass substrate acts as the sacrificial material. Due to the extreme high intensity of the tightly focused femtosecond laser beam, nonlinear processing occurred between photoresist and the laser pulses, which enable the sub-micron feature processing. In the experiments, we use a translational stage that is controlled by a computer to accurately move for fabrication of optical elements with high precision. Various gratings and phase plates are fabricated by this method. The obtained gratings patterns are checked with a conventional optical microscopy. The fabricating widths and depths are measured with the Taylor Hobson equipment. With the same method, photomask for microelectronics can also be fabricated. From the experimental results, we see that a high processing precision and the feature size exceeding the diffraction limit can be achieved with this method. This technique can be applied to the fields of microoptics and microelectronics. The mechanism between femtosecond laser and photoresist is also investigated. The processing mechanics is considered as laser ablation and nonlinear two-photon absorption phenomenon. Fabrication of optical elements with femtosecond laser reflects a new trend for fabrication of microoptical elements.

A novel optical PCB with transmitter/receiver system boards and optical bakcplane was prepared, which is board-to-board interconnection by optical plug and slot. We report an 8Gb/s PRBS NRZ data transmission between transmitter system board and optical backplane embedded multimode polymeric waveguide arrays. The basic concept of ETRI's optical PCB is as follows; 1) Metal optical bench is integrated with optoelectronic devices, driver and receiver circuits, polymeric waveguide and access line PCB module. 2) Multimode polymeric waveguide inside an optical backplane, which is embedded into PCB. 3) Optical slot and plug for high-density(channel pitch : 500um) board-to-board interconnection. The polymeric waveguide technology can be used for transmission of data on transmitter/ receiver system boards and for backplane interconnections. The main components are low-loss tapered polymeric waveguides and a novel optical plug and slot for board-to-board interconnections, respectively. The optical PCB is characteristic of low coupling loss, easy insertion/extraction of the boards and, especially, reliable optical coupling unaffected from external environment after board insertion.

A low cost prototype of a laser range finder using a CMOS image sensor is developed for the automotive field. The system presented here is based on triangulation. The gravity of the infrared laser spot on CMOS image sensor is converted into pixel coordinates proportional to the distance to be measured. Based on the experimental tests of the system, it was found that the distance could be estimated with accuracy better than 5% within the range of 5 to 45 meters at twilight and night. Experimental results are provided and possible improvements are discussed.

We have proposed a miniaturized optical signal pickup module comprised of several SiNX membrane devices on stacked Si substrates for use in optical storage system. The optical module was designed to include not only light sources and detectors, but also the diffractive optical elements (DOEs), which can be made with microoptoelectromechanical systems (MOEMS) technology. Its optical operation was simulated by ray-tracing to have an optimized spot size (~0.6μm) focused on the disk with setting the tolerance of each element for the alignment. All these Si-based transmission optical elements were fabricated and can be stacked by self-alignment bonding for system assembly.

Recently, integral imaging attracted a lot of researchers as one powerful candidate for the three-dimensional display. However the limitation on the image depth of integral imaging is considered as the major obstacle for the practical use. Previously, a number of researches reported on the analysis of such limitation based on the diffraction of light. But there exists the severe mismatch between the experimental results and the simulation results that appear in the previous researches. In this paper, we propose a new assumption that exactly predicts the experimental results. Based on that new assumption, we propose the quantitative method to evaluate the image depth of integral imaging. We also propose the elemental image correction scheme that removes the distortion of the integrated image located out of the central depth plane.

Detecting depth information from a pickup image of integral imaging is of great importance since it is the first step for providing integral imaging systems with some flexibility against various system specifications and display environment. One problem of the depth extraction in the integral imaging is that the gap between the lens array and the elemental image plane cannot be determined exactly since the desired value depends on the object depth itself. Moreover, an object to be picked up is preferred to be located close to the lens array to ensure sufficient resolution in the elemental image and the detected depth profile, which makes the gap deviate too far from the focal length of the lens array, and thus disturbs exact depth extraction. In this paper, we propose a depth extraction method using a uniaxial crystal in addition to the lens array. The proposed system can detect the depth without prior knowledge of gap between the lens array and the elemental image plane. We explain the principle and verify it by simulation and experimental results.

The lowest detectable fluorescence signal level from biomedical specimens have been determined using a spectrometer, cooled CCD detector, and PIN photodiode with 365 nm UV LED light excitation. The data indicates the PIN photodiodes have adequate sensitivity for detection of tissue fluorescence with a sufficient signal-to-noise ratio. This data is being used to design a "pill-sized" Compact Photonics Explorer (CPE) for in vivo cancer optical diagnostics.

Thin-film optical filters selectively absorb, transmit and reflect certain parts of the electromagnetic spectrum. We propose and analyze a new concept of thin-film filter that directly and selectively transmits and reflects certain parts of the spectrum of spatial frequencies. The transmittance and reflectance are short-pass functions or long-pass functions of the angle of incidence. We discuss optical filters designed with dielectric thin films between two right angle prisms to selectively cancel a reflected or transmitted plane wave front for different angles of incidence. A detailed analysis of these optical filters with respect to the index of refraction of the films and prisms, width of films, and polarization of light is presented. Applications on extrasolar planet detection are briefly discussed.

In this paper, a new software-oriented autostereoscopic 4-view imaging & display system for web-based 3D image communication is implemented by using 4 digital cameras, Intel Xeon server computer system, graphic card having four outputs, projection-type 4-view 3D display system and Microsoft' DirectShow programming library. And its performance is also analyzed in terms of image-grabbing frame rates, displayed image resolution, possible color depth and number of views. From some experimental results, it is found that the proposed system can display 4-view VGA images with a full color of 16bits and a frame rate of 15fps in real-time. But the image resolution, color depth, frame rate and number of views are mutually interrelated and can be easily controlled in the proposed system by using the developed software program so that, a lot of flexibility in design and implementation of the proposed multiview 3D imaging and display system are expected in the practical application of web-based 3D image communication.

In the article the structural model, realized by the authors, is described. This model helps to formalize description of a configuration of optical system. It allows to solve special tasks such as: analysis of a layout (a graphic image) of the optical scheme, comparison of morphological (structural) distinctions of the optical schemes, classification of optical systems by their configuration.

We developed a method of extending the depth of field of a microscope objective specifically used in an imaging system designed for small particle tracking. We extended the depth of field by inserting a quartic phase plate near the aperture stop plane of an objective. An optimum quartic phase plate was designed for a conventional 100X/0.8 microscope objective, and the simulation results predicated that the depth of field of the new objective could be increased more than twofold in comparison with an objective having no such phase plate.

This paper reports the experimental research result for the measurement of laser pot size and the beam waist with a new method, basic on that a new type detector fabricated with monocrystalline silicon. The design idea for the detector was demonstrated right and doable theoretically and experimentally, with new approach, the so-called "pre-saturation" of silicon. This new detector can detect the size of laser beam pot quickly and accurately, with wide response wavelength band and quite small expense. Also in this work, an interesting novel phenomenon, some abnormal variations of photo- voltage, is observed. For that the model of "competition between photons" set up to give a good qualitative interpretation, which leaded to the final success of experiment design.

We have simulated Chirped Pulse Amplification process with a new software, allowing to extend the generally used 1D-models. We show here the importance of the beam spatial discretization in simulations in order to describe the gain saturation. Experimental measurements performed on our 100 TW laser validate this calculation, allowing us to carefully design the next generation of Ti:sapphire lasers at the Petawatt level.