Traditional zoom lens designs employ multiple moving lens elements to provide simultaneous control of focal length and focal plane. We present an approach to a design of a simplified zoom lens by employing a single moving element to control only the focal length. We show that the defocus in miniaturized zoom lenses with a single moving element can be corrected by the use of wavefront coding, although this introduces a modest reduction in signal-noise-ratio. As an example, we present a design of a miniaturized 10 mm long wavefront coded 2.3x optical zoom lens with a single moving lens element.

The standard imaging lens for a high resolution sensor was modified to achieve the extended depth of field (EDoF) from 300 mm to infinity. In the module the raw sensor outputs are digitally processed to obtain high contrast images. The overall module is considered as an integrated computational imaging system (ICIS). The simulation results for illustrative designs with different amount of spherical aberrations are provided and compared. Based on the results of simulations we introduced the limiting value of the PSF Strehl ratio as the integral threshold criteria to be used during EDoF lens optimization. A four-element standard lens was modified within the design constraints to achieve the EDoF performance. Two EDoF designs created with different design methods are presented. The imaging modules were compared in terms of Strehl ratios, limiting resolution, modulation frequencies at 50% contrast, and SNR. The output images were simulated for EDoF modules, passed through the image processing pipeline, and compared against the images obtained with the standard lens module.

The design of modern imaging systems is intricately concerned with the control of optical aberrations in systems that can be manufactured at acceptable cost and with acceptable manufacturing tolerances. Traditionally this involves a multi-parameter optimisation of the lens optics to achieve acceptable image quality at the detector. There is increasing interest in a more generalised approach whereby digital image processing is incorporated into the design process and the performance metric to be optimised is quality of the image at the output of the image processor. This introduces the possibility of manipulating the optical transfer function of the optics such that the overall sensitivity of the imaging system to optical aberrations is reduced. Although these hybrid optical/digital techniques, sometimes referred as wavefront coding, have on occasion been presented as a panacea, it is more realistic to consider them as an additional parameter in the optimisation process. We will discuss the trade-offs involved in the application of wavefront coding to low-cost imaging systems for use in the thermal infrared and visible imaging systems, showing how very useful performance enhancements can be achieved in practical systems.

In this paper we present an approach to obtain an extended Depth-of-Field (DoF) for cell phone miniature camera by jointly optimizing optical system and post-capture digital processing techniques. Using a computational imaging approach, we demonstrate how to increase, to a useful operating range, the effective DoF of a specifically designed fixed focus lens operating e.g. at f/2.8. This is achieved with a lens design where the longitudinal chromatic aberration has been increased. This increase is controlled so as to have, for any distance within the extended DoF, at least one colour channel of a RGB image which contains the in-focus scene information (e.g. high frequencies). By determining the sharpest colour (for each region in the digital image) and reflecting its sharpness on the others, we show that it is possible to get a sharp image for all colours through the merged DoF of the three of them. We compare our technique with other approaches that also aimed to increase the DoF such as Wavefront coding.

The integration of novel optics designs, miniature CMOS sensors, and powerful digital processing into a single imaging module package is driving progress in handset camera systems in terms of performance, size (thinness) and cost. The miniature cameras incorporating high resolution sensors and fixed-focus Extended Depth of Field (EDOF) optics allow close-range reading of printed material (barcode patterns, business cards), while providing high quality imaging in more traditional applications. These cameras incorporate modified optics and digital processing to recover the soft-focus images and restore sharpness over a wide range of object distances. The effects a variety of parameters of the imaging module on the EDOF range were analyzed for a family of high resolution CMOS modules. The parameters include various optical properties of the imaging lens, and the characteristics of the sensor. The extension factors for the EDOF imaging module were defined in terms of an improved absolute resolution in object space while maintaining focus at infinity. This definition was applied for the purpose of identifying the minimally resolvable object details in mobile cameras with bar-code reading feature.

Due to the application of mobile phone lens, the clear image for the different object distance from infinity to close-up creates a new bargaining. We found that wave-front coding applied to extend the depth of field may solve this problem. By means of using cubic phase mask (CPM), the blurred point-spread function (PSF) is substantially invariant to defocus. Thus, the ideal hyperfocal distance condition can be satisfied as long as the constant blurred image can eventually be recovered by a simple digital signal processing. In this paper, we propose a different design method of computational imaging lens for mobile phone up to ideal depth of field based on PSF focus invariance. Because of the difficulty for comparing the similarity to different PSFs, we define a new metric, of correlation, to evaluate and optimize the PSF similarity. Besides, by means of adding the anti-symmetric free form phase plate at aperture stop and using the correlation and Strehl ratio as the two major optimization operands, we can get the optimum phase plate surface to achieve the required extended depth of field (EDoF). The resulted PSF on focal plane is significantly invariant to object distance varying from infinity to 10cm.

The design of the first Real-Time-Tomographic-Holography (RTTH) optical system for augmented-reality applications is presented. RTTH places a viewpoint-independent real-time (RT) virtual image (VI) of an object into its actual location, enabling natural hand-eye coordination to guide invasive procedures, without requiring tracking or a head-mounted device. The VI is viewed through a narrow-band Holographic Optical Element (HOE) with built-in power that generates the largest possible near-field, in-situ VI from a small display chip without noticeable parallax error or obscuring direct view of the physical world. Rigidly fixed upon a medical-ultrasound probe, RTTH could show the scan in its actual location inside the patient, because the VI would move with the probe. We designed the image source along with the system-optics, allowing us to ignore both planer geometric distortions and field curvature, respectively compensated by using RT pre-processing software and attaching a custom-surfaced fiber-optic-faceplate (FOFP) to our image source. Focus in our fast, non-axial system was achieved by placing correcting lenses near the FOFP and custom-optically-fabricating our volume-phase HOE using a recording beam that was specially shaped by extra lenses. By simultaneously simulating and optimizing the system's playback performance across variations in both the total playback and HOE-recording optical systems, we derived and built a design that projects a 104x112 mm planar VI 1 m from the HOE using a laser-illuminated 19x16 mm LCD+FOFP image-source. The VI appeared fixed in space and well focused. Viewpoint-induced location errors were <3 mm, and unexpected first-order astigmatism produced 3 cm (3% of 1 m) ambiguity in depth, typically unnoticed by human observers.

In this paper, we present the design of a 0.2 NA microscope objective operating across a 120nm broadband spectral range that requires only two doublets and an embedded liquid lens to achieve 3 μm invariant lateral resolution throughout a large 8 cubic millimeter imaging sample. Achieving invariant lateral resolution comes with some sacrifice in imaging speed, yet in the approach proposed, high speed in vivo imaging is maintained up to a resolution of 3 μm for a 2x2 mm sample size. Thus, in anticipation to ultimately aim for a resolution of 0.5 to 1 μm, we are investigating the possibility to further gain in resolution using super-resolution methods so both hardware solutions and image processing methods together can provide the best trade-off in overall resolution and speed of imaging. As a starting point to investigate super-resolution methods, we evaluate in this paper three well-known super-resolution algorithms used to reconstruct a high resolution image from down-sampled low resolution images of an African frog tadpole acquired en face using our OCM set-up. To establish ground truth necessary for assessment of the methods, low resolution images were simulated from a high resolution OCM image. The specification and design performance of the custom designed microscope will be presented as well as our first results of super-resolution imaging. The performance of each algorithm was analyzed and all performances compared using two different metrics. Early results indicate that super-resolution may play a significant role in the optimization of high invariant resolution OCM systems.

In this paper, we summarize our initial experiences in designing head-worn displays with free-form optical surfaces. Typical optical surfaces implemented in raytrace codes today are functions mapping two dimensional vectors to real numbers. The majority of optical designs to date have relied on conic sections and polynomials as the functions of choice. The choice of conic sections is justified since conic sections are stigmatic surfaces under certain imaging geometries. The choice of polynomials from the point of view of surface description can be challenged. The advantage of using polynomials is that the wavefront aberration function is typically expanded in polynomials. Therefore, a polynomial surface description may link a designer's understanding of wavefront aberrations and the surface description. The limitations of using multivariate polynomials are described by a theorem due to Mairhuber and Curtis from approximation theory. In our recent work, we proposed and applied radial basis functions to represent optical surfaces as an alternative to multivariate polynomials. We compare the polynomial descriptions to radial basis functions using the MTF criteria. The benefits of using radial basis functions for surface description are summarized in the context of specific magnifier systems, i.e., head-worn displays. They include, for example, the performance increase measured by the MTF, or the ability to increase the field of view or pupil size. Full-field displays are used for node placement within the field of view for the dual-element head-worn display.

The importance of condenser optics is the fact that it is the bottleneck limiting efficiency in commercially available projection systems. Efficiency is a key parameter of projector performance, since it augments screen luminance, enabling the system to perform well under increasing levels of ambient light. Conventional condensers use rotational symmetric devices, most of them being elliptic or parabolic mirrors. They perform very far from the theoretical limits for sources such as arc lamps or halogen bulbs. Typical small displays in the 5-15 mm² etendue range have geometrical efficiencies about 40-50% for the best condensers; although theory allows about 100% (no reflection nor absorption losses are considered). Two basic facts are underlying this effect: The coma aberration of the reflectors and the rotational symmetric image of the source making the source projected image to unfit with the target. Thus, the only way to improve this performance is to generate a free form design that is able to control the shape and rotation of the source projected images. As yet, this can only be done with the SMS3D design method. We present here one of such designs achieving a geometrical efficiency that is 1.8 times that of an elliptical condenser for a 4:1 target aspect ratio and for the range of target etendue with practical interest and 1.5 for 16:9 target. This design uses only 1 additional reflection, i.e., uses a total of 2 reflections from the source to the target. A prototype of this free form condenser has already been built.

In order to bound yet keep realistic optical shapes for freeform illumination optics, fractional optimization is employed. By allowing the shape variables to freely vary, optimization leads to bizarre shapes that cannot be manufactured. Therefore, fractional shape variables that are referenced to other system variables are set. Optimization of the pseudo-collimation of an LED using a hybrid optic is presented. The shape of the hybrid optic is described by non-uniform rational B-splines (NURBS). Two examples of this system are optimized: maximum transfer efficiency into an intensity distribution of ±10° and maximum transfer and uniformity over this same angular range.

The simultaneous multiple surface (SMS) method has been used to design nonimaging devices, such as solar concentrators and collimators, which work near the thermodynamic limit at highest efficiencies. The very high compactness of these devices is obtained through the simultaneous design of two high-order (above 30th) aspheric surfaces. In imaging optics, low-order aspheric surfaces were introduced to correct Seidel aberrations. The ease with which the SMS method calculates higher-order aspheric surfaces offers great advantages in imaging design. The SMS method can design N rotationally-symmetric surfaces that, by definition, form sharp images of N one-parameter subsets of rays. The design strategy consists in finding the best configuration of these subsets of rays in phase-space, one that ensures that image-quality specifications will be met by all non-design rays. As a first example of an SMS imaging device, a new video projection optics system is presented, featuring extremely short throw distance, high compactness and wide angle projection.

Optimization of traditional optical systems involves defining a merit function and a corresponding set of variables. The variables are changed to configure the optical system for optimum performance as required from the merit function. The typical variables used in lens design codes for designing classical optical systems are surface curvature, conic constant, aspheric coefficients, thickness, and refractive indices. The surface curvature, conic constant and aspheric coefficients are related directly to a polynomial equation representation of the surface. However, sometimes these variables are not the best choice for optimization especially in illumination system design where the required optical prescription is in the form of computer aided design (CAD) geometrical representation. As an alternative to these traditional variables, optimization using rational Bézier control points and weighting factors as variables is proposed and explored in this paper. Non-uniform rational B-splines (NURBs) using the Bézier basis are natural, graphical design curves exhibiting end-point interpolation whose interior control points and weighting factors are ideal variables for optical system optimization. Furthermore, optical designs created with NURBS are already in the language of CAD and numerical control machining environments and do not require the troublesome process of converting polynomial surfaces to their parametric representations.

In the quest to design large and extremely large telescopes, one of the first questions encountered is that of basic optical configuration and shape of the primary mirror. Spherical mirrors have a number of advantages in production, testing and alignment but suffer from substantial spherical aberration, thereby requiring some form of corrective optics. Many designs for spherical aberration correctors are present in the literature, but each has its strengths and weaknesses. We present the design for a new spherical aberration corrector which is believed to offer higher performance with less complexity than previous approaches. The new design is substantially more compact and uses slower optical surfaces than most axially symmetric designs. It can scale to accommodate apertures as large as 100m, and adapts equally well to post prime focus and Cassegrain-like focus applications.

The European Space Agency (ESA)[1] foresees several robotic missions aimed for the preparation of the future Human Exploration of Mars. To accomplish the mission objectives Imaging LIDARs are one of the identified technologies that shall provide essential information to the spacecraft Guidance, Navigation and Control (GN&C) system. ESA awarded two technology development contracts to two industrial teams for the development and demonstration of novel technologies for Imaging LIDAR sensors. Both teams designed and are manufacturing an Imaging LIDAR breadboard targeting one specific application. The objective of using novel technologies is to reduce substantially the mass and power consumption of Imaging LIDAR sensors. The Imaging LIDAR sensors shall have a mass <10kg, power consumption <60Watt, measure distances up to 5000m, with a field of view (FOV) of 20x20 degrees, range resolutions down to 2 cm, and a frame rate higher than 1 Hz.

We have developed the Space Imaging Infrared Optical Guidance for Autonomous Ground Vehicle based on the uncooled infrared camera and focusing technique to detect the objects to be evaded and to set the drive path. For this purpose we made servomotor drive system to control the focus function of the infrared camera lens. To determine the best focus position we use the auto focus image processing of Daubechies wavelet transform technique with 4 terms. From the determined best focus position we transformed it to the distance of the object. We made the aluminum frame ground vehicle to mount the auto focus infrared unit. Its size is 900mm long and 800mm wide. This vehicle mounted Ackerman front steering system and the rear motor drive system. To confirm the guidance ability of the Space Imaging Infrared Optical Guidance for Autonomous Ground Vehicle we had the experiments for the detection ability of the infrared auto focus unit to the actual car on the road and the roadside wall. As a result the auto focus image processing based on the Daubechies wavelet transform technique detects the best focus image clearly and give the depth of the object from the infrared camera unit.

The Raman analysis of common, non-absorbing gases was performed using an 18@1 fiber-optic probe coupled to a multi-pass capillary cell (MCC) for signal enhancement. The MCC is fabricated by metal-coating, using silver or other highly reflective metals, the inside of a 1-2 mm diameter glass capillary using commercially available silvering solutions and provides enhancements up to 30-fold over measurements using the fiber-optic probe alone. The design of the MCC is simple and the device is easy to incorporate into an experimental setup making it suitable for remote and <i>in-situ</i> analysis. Although the MCC is functionally similar to liquid-core waveguides that have been previously described in the literature, the MCC is not based on total internal reflection and so the refractive index of the analyte is not important to the operation of the device. The principle of operation of the MCC is similar to mirror-based multiple pass Raman cells, however, the MCC is not expensive, alignment is trivial and an optical path length up to several meters in length is possible. With our first-generation silver-coated MCCs, limits of detection were determined to be 0.02% and 0.2% for CH₄ and CO₂ respectively. In this talk we will discuss optimization of the MCC and issues involved in its use.

Miniaturized imaging systems have become ubiquitous as they are found in an ever-increasing number of devices, such as cellular phones, personal digital assistants, and web cameras. Until now, the design and fabrication methodology of such systems have not been significantly different from conventional cameras. The only established method to achieve focusing is by varying the lens distance. On the other hand, the variable-shape crystalline lens found in animal eyes offers inspiration for a more natural way of achieving an optical system with high functionality. Learning from the working concepts of the optics in the animal kingdom, we developed bio-inspired fluidic lenses for a miniature universal imager with auto-focusing, macro, and super-macro capabilities. Because of the enormous dynamic range of fluidic lenses, the miniature camera can even function as a microscope. To compensate for the image quality difference between the central vision and peripheral vision and the shape difference between a solid-state image sensor and a curved retina, we adopted a hybrid design consisting of fluidic lenses for tunability and fixed lenses for aberration and color dispersion correction. A design of the world's smallest surgical camera with 3X optical zoom capabilities is also demonstrated using the approach of hybrid lenses.

A novel design of a wavefront coded compact camera system with liquid lens is presented. The point spread function must remain practically constant over a wide range of defocus in order to create an image which is sharp over a large depth of field. Therefore, the trade-off between the effect of extended depth of field and reduction in the signal to noise ratio of the restored image become critical. By combining liquid lens and wavefront coding, the system can deliver much greater depth of field without the restoration problems caused by the similarity of point spread function. This could improve the overall image performance.

The purpose of this study is to analyze the optical properties of a liquid lens and design a magnetism-driven mechanism for that lens. The lens is composed of a base plate, a glass covered liquid reservoir, a flexible membrane (which is opposite to the glass side of the liquid reservoir), a disk with an o-ring, a spring, three permanent magnets, and three solenoids. The permanent magnets are fixed on the disk, which is used to control the displacement of the o-ring. The o-ring is on the top of the membrane and is designed to move the o-ring. When the solenoid is operated, the o-ring squeezes the membrane, the curvature of the membrane is changed and the focus can be varied according to the magnitude of curvature change. The aberration of the lens can be obtained through analysis by substituting the membrane profile into ZEMAX software. The effect of different ring diameter and thickness to the spherical aberration is analyzed. Finally, a detail magnetism-driven mechanism is designed and discussed.

The purpose of this study is to present a design concept of a variable focus gradient index liquid lens. The concept of the design is utilized a method which involve powder in liquid and the powder is driven by electrical magnetic force. This lens is composed of a barrel, liquid, powder in liquid and electrical magnetic-driven control device. The electrical-magnetic control device is used to control the powder distribution in the liquid; the controlled powder distribution makes the lens becomes a gradient optical index lens. When the electrical magnetism-driven control device operates, the lens optical index decreases from centric to rim in radial direction gradually. The focused position can be varied when the electrical magnetism-driven controlled device operates in different conditions. Finally, a prototype is set up and experiment is conducted. Application and analysis of the design concept is also discussed.

Three Rivers Community College offers two associate degree programs in optics/photonics, and graduates have their choice of jobs in New England and across the United States. Nonetheless, students, their parents, teachers and guidance counselors are largely unaware of the career opportunities in the photonics industry. To promote optics/photonics career awareness, we hosted two versions of "Laser Camp" in 2007 and 2008. Hands-on activities were chosen to promote awareness of optical science and technology careers and to provide "take home" information and souvenirs to share with family and friends. In this paper, we discuss the logistics of funding, marketing, permissions, transportation and food service and share our student-tested activities.

Problem-based learning (PBL) is an instructional approach in which students learn by actively and collaboratively solving authentic problems encountered in real-world situations. Research demonstrates that PBL improves students' learning and retention, motivation, critical thinking and problem-solving skills, and their ability to skillfully apply knowledge in new and novel situations - skills deemed critical for lifelong learning. In this paper, we present the Photon PBL project, a three-year National Science Foundation Advanced Technological Education (NSF-ATE) project aimed at developing, in partnership with photonics industry and university partners, a comprehensive series of multimedia PBL instructional materials and training for photonics technology educators from across the US and abroad. Results from first-year pilot testing of multimedia PBL instructional materials, problem development and implementation strategies are detailed.

A new course for technical high school students has been developed that integrates components of technical shops into a one-semester Introduction to Optics classroom curriculum. Hands-on activities based on the discovery model are used to build confidence in students who are weak in mathematics. The course promotes career awareness through collaboration with nearby community colleges and activities such as Laser Camp. In this paper we discuss the development and implementation of the course and its relationship to the PHOTON2 and PHOTON PBL projects.

In 1929, a grant from Eastman Kodak and Bausch and Lomb established The Institute of Optics as the nation's first academic institution devoted to training optical scientists and engineers. The mission was 'to study light in all its phases', and the curriculum was designed to educate students in the fundamentals of optical science and build essential skills in applied optics and optical engineering. Indeed, our historic strength has been a balance between optical science and engineering--we have alumni who are carrying out prize-winning research in optical physics, alumni who are innovative optical engineers, and still other alumni who are leaders in the business community. Faculty who are top-notch optical engineers are an important resource to optical physics research groups -- likewise, teaching and modeling excellent optical science provides a strong underpinning for students on the applied/engineering end of the spectrum. This model -an undergraduate and graduate program that balances fundamental optics, applied optics, and optical engineering- has served us well. The impressive and diverse range of opportunities for our BS graduates has withstood economic cycles, and the students graduate with a healthy dose of practical experience. Undergraduate advisors, with considerable initiative from the program coordinator, are very aggressive in pointing students toward summer research and engineering opportunities. The vast majority of our undergraduate students graduate with at least one summer of experience in a company or a research laboratory. For example, 95% of the class of 2008 spent the summer of 2007 at companies and/or research laboratories: These include Zygo, NRL, Bausch and Lomb, The University of Rochester(The Institute of Optics, Medical Center, and Laboratory for Laser Energetics), QED, ARL Night Vision laboratories, JPL, Kollsman, OptiMax, Northrup Grumman, and at least two other companies. It is an impressive list, and bodes well for the career preparation for these students. While this extracurricular experience is truly world-class, an integrated design experience defined within our academic program is increasingly necessary for those going on to professional careers in engineering. This paper describes the philosophy behind a revision to our undergraduate curriculum that integrates a design experience and describes the engineering laboratory that has been established to make it a reality. The laboratory and design center has been named in honor of Robert E. Hopkins, former director and professor, co-founder of Tropel corporation, and a lifelong devotee to engineering innovation.

With minimization of optical-electronics devices, conventional optical zoom lens component has been explored with liquid lens and soft polymer membranes. This paper introduces a novel zoom lens system with a soft polymer material, Polydimethylsiloxane (PDMS), its shape and curvature can be controlled by pneumatic pressure. Therefore, effective focal length (EFL) of soft zoom lens (SZL) system can be controlled and altered. According to desired opto-mechanical design, this ZL has been accessed to determine the optical specifications. After the pressure activated from 0 to 0.02MPa, the change of EFL of the SZL system can reach up to 18.77% (33.44mm to 39.717mm). Experimental results show that zoom effects of the developed SZL system are significantly affected by the shape, thickness and curing parameter of PDMS soft lens. The SZL system has been verified with the function of zoom ability. Further research works on the integration of the SZL system with imaging system for mobile devices or robot vision applications.

A diagnostic instrument has been developed for the acquisition of high-speed time-resolved images at the Dual-Axis Radiographic Hydrodynamic Test (DARHT) Facility at Los Alamos National Laboratory. The instrument was developed in order to create time histories of the electron beam. Four discrete optical subsystems view Cerenkov light generated at an x-ray target inside of a vacuum envelope. Each system employs cylindrical optics to image light in one direction and collapse light in the orthogonal direction. Each of the four systems images and collapses in unique axes, thereby capturing unique information. Light along the imaging axis is relayed via optical fiber to streak cameras. A computer is used to reconstruct the original image from the four optically collapsed images. Due to DARHT's adverse environment, the instrument can be operated remotely to adjust optical parameters and contains a subsystem for remote calibration. The instrument was deployed and calibrated, and has been used to capture and reconstruct images. Matters of alignment, calibration, control, resolution, and adverse conditions will be discussed.

This research proposes a new method of optical system optimization for both optics and image processing, as a route to achieving best performance. Traditionally, optics is optimized independently without taking account of image processing. In this research, optimization work will be further studied with the concept of digital image processing (DIP), point spread function (PSF) and modulation transfer function (MTF), in order to reduce the size of miniature zoom lenses without sacrificing image quality. Experimental results show that optimization taking account of image processing yields much better performance than optimization which ignores it. From another point of view, it is concluded that equivalent performance may be achieved in the following two cases: one is having a poor lens with optimization work combined with image processing; the other is good optics without optimization work combined with image processing.

One of the big advantages of polymer optics is the possibility of integrating several functions into one component. These functions can range from mechanical reference datums all the way to micro channels in "lab-on-chip" type of applications. In this paper an overview on several design- and manufacturing principles of such integrated components will be given. Furthermore the next steps in the Design - Build - Test cycle will be discussed as well: mold manufacturing, molding and finally metrology.

The design, fabrication, and properties of one of a new class of gradient-index lenses are reported. The lens is an f/2.25 GRIN singlet based on a nanolayered polymer composite material, designed to correct for spherical aberration. The light gathering and focusing properties of the polymer lens are compared to a homogeneous BK7 glass singlet with a similar f-number. The modulation transfer function of the polymer GRIN lens exceeded that of the homogeneous glass lens at all spatial frequencies and was as much as 3 times better at 5 cyc/mm. The weight of the polymer lens was approximately an order of magnitude less than the homogeneous glass lens.

Polyimides are attractive mirror candidate materials due to their low mass, solar radiation resistance, and cryogenic flexibility. However, polyimides exhibit high coefficients of thermal expansion (CTE) values (40-70 ppm/K), inducing image distortion from CTE mismatch. Additionally, the temperature of large aperture (10 m) membranes is not uniformly controlled in space, further increasing image distortion from anisotropic deformations. The CTE of the MSRS Novastrat polyimide line was adjusted to exhibit CTEs between -16 ppm/K and 53 ppm/K, including 0 ppm/K, 10 ppm/K, 17 ppm/K, and 25 ppm/K corresponding with CTE matches of graphite/epoxy, carbon steel, copper, and aluminum (respectively). The development of these CTE-matched membranes is presented, as well as the effect of the CTE adjustment on the mechanical properties.

Hardcoats are frequently used on polycarbonates and other optical plastics to increase durability by improving scratch and abrasion resistance. The current study compares several commercially available hardcoats, both dip-coated and vacuum-deposited materials. Compatibility of the hardcoat with vacuum deposited optical coats is considered. The successive layers of optical coat and hardcoat on the polycarbonate result in non-uniform spectral content and visible fringing effects due to thickness variation and thin-film interference. Experimental results and model correlation are presented.

ABCO Tool & Die, Inc. is a mold manufacturer specializing in the manufacturing of plastic injection molds for molded optical parts. The purpose of this presentation is to explain the concepts and procedures required to build a mold that produces precision optical parts. Optical molds can produce a variety of molded parts ranging from safety eyewear to sophisticated military lens parts, which must meet precise optical specifications. The manufacturing of these molds begins with the design engineering of precision optical components. The mold design and the related optical inserts are determined based upon the specific optical criteria and optical surface geometry. The mold manufacturing techniques will be based upon the optical surface geometry requirements and specific details. Manufacturing processes used will be specific to prescribed geometrical surface requirements of the molded part. The combined efforts result in a robust optical mold which can produce molded parts that meet the most precise optical specifications.

The first step of the polymer optics process chain after finishing the optical design is the mold fabrication. Typically the mold is fabricated by a number of process steps including ultra precision diamond turning or milling. Often a manual polishing is necessary to get rid of the turning or milling marks. In contrary to the existing mold manufacturing process chain we develop a new two step mold manufacturing process capable for freeform optics. It consists of a milling step followed by a Computer Controlled Polishing. First results of the new process chain for mold fabrication including the replicated polymer optics will be reported in this paper.

We report about properties of epoxy novolak resin polymer doped with dysprosium ions. The polymer layers were fabricated by spin-coating onto silicon substrates, or pouring epoxy novolak resin solution into bottomless molds placed on a quartz substrate and leaving them to dry. Rather strong bands around 3366 cm^-1 in the infrared spectra indicated presence of the O-H groups. Absorption measurements were done in the spectral range from 300 nm to 3000 nm and showed six strong bands at 758 nm (⁶F_3/2), 807 nm (⁶F_5/2), 906 nm (⁶F_7/2), 1100 nm (⁶F_9/2), 1280 nm (⁶F_11/2) and 1685 nm (⁶H_11/2) corresponding to Dy³⁺ ions. Optical band gap E_g was determined from the absorption coefficient values using Tauc's procedure, i.e., from the relationship αhv = A(hv - E_g)² and the obtained values varied from 3.489 eV to 3.539 eV depending on the amount of dysprosium ions involved in the samples. Photoluminescence spectra around 1300 nm were investigated by using excitation of He-Ne laser (632.8 nm) and two semiconductor lasers (980 nm and 827 nm).

As polymers become more widely used in optics antireflective coatings need to be designed specifically to suit these new components. Modifications are being made to the current high temperature coating process to allow for inorganic metal oxides to be applied to polymer optics. This is not however the only hurdle that needs to be overcome to produce a satisfactory antireflective coating on polymers. Inorganic metal oxides and polymer components have a significant difference in thermal expansion meaning that defects such as delamination and cracking can occur. These defects significantly shorten the lifetime of the optical component. A new antireflective coating has been developed that has a similar thermal expansion coefficient to that of the polymer substrate, meaning that defects caused by thermal stress do not occur. These are polymeric coating with a refractive index of 1.31 and 1.34, lower than that of magnesium fluoride (MgF₂) at 1.38. These coatings have antireflective properties superior to those of current commercially available single layer inorganic antireflective coatings. Polymer antireflective coatings cannot be applied by vacuum deposition. Dip coating was evaluated as a method for film application. Dip coating allows control of the film thickness through varying the properties of the coating solution. It also allows for uniform films that can be inspected visually for variances.