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We have designed, fabricated, and tested hybrid refractive/diffractive optical elements in acrylic and cyclic olefin copolymer polymers. The elements were tested for optical performance before and after various environmental conditions.

The DARPA-funded Consortium for Optical and Optoelectronic Technologies for Computing (CO-OP) recently completed the first DOE Foundry run delivering ten samples to each of nineteen users, each with a unique design. The binary optics process was used to provide a maximum of eight phase levels at a design wavelength of 850 nm. Averaged over all users and all samples, an etch depth error of one percent and alignment accuracy within 0.25 micron were achieved. This paper summarizes the details of the process results.

A diffractive optical surface was inserted in a wide field of view ultraviolet sensor to increase the aperture and waveband of the system with no increase in size or weight. The diffractive optical surface was etched in sapphire using binary optics fabrication techniques.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We present an overview of diffractive optics technology and the advantages this technology offers when applied to head-mounted displays (HMD). We show especially the impact on weight reduction when diffractive elements are used to correct chromatic aberrations in full-color HMDs. We discuss the effect of higher diffractive orders on image quality and show how to model these effects. Finally, we present the results of a demonstration of a diffractive element in a conventional monochromatic HMD, compare the performance of the hybrid and conventional systems, and demonstrate the validity of our model.

Honeywell Inc. and Mission Research Corporation (MRC) are jointly developing micro resistive heater array displays for projecting dynamic background scenes and targets in the short-wavelength infrared (SWIR) to long-wavelength infrared (LWIR) wavebands. There are two joint government contracts supporting this work: the Nuclear Optical Dynamic Display (NODDS) program under DNA contract DNA001-92-C-0041, which is developing a 512 X 512 array of 50- by 50-micrometers display pixels, and the Cryovacuum Resistor Infrared Scene Projector (CRISP) program for the USAF Wright Laboratory at Eglin AFB, which is developing a 512 X 512 array of 87.5- by 87.5-micrometers pixels. The requirements on the two programs are somewhat different due to their different missions. While the NODDS program is developing an array that can be used to create dynamic nuclear clutter scenes, the CRISP arrays are being designed for simulating multiple independently moving targets; and while the frame rate on the NODDS arrays requires an array capable of 1-kHz frame rates, the CRISP arrays will be operated at 30 Hz.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We present results characterizing the effects of processing errors on the performance of staircase kinoforms, commonly known as `binary optical devices.' Diffraction efficiency and modulation transfer function data are given for various types of processing errors present in staircase kinoforms of a f/10 Fresnel phase lens having two, four, and eight phase levels. Processing errors include etch depth, linewidth, and mask alignment. Processing errors, especially mask alignment, are shown to have the greatest impact on diffraction efficiency and very little effect on image quality.

This paper describes the fabrication and testing of 64 X 96 arrays of microlenses used for fill-factor enhancement of uncooled infrared detector arrays. Each lenslet represents a f/0.9 Fresnel phase lens at 10 micrometers wavelength. All arrays were etched into silicon wafers as either 8-level or 16-level staircase kinoforms. When integrated with a detector array having 20 fill factor, these microlens arrays were capable of increasing the magnitude of the measured signal with f/2.2 fore-optics by 2.5-fold.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Proces s-dependent kinoform performanceJ.A. Cox, B. Fritz, T. WernerHoneywell Systems & Research Center10701 Lyndale Avenue SouthBloomington, MN 55420ABSTRACTWe present results of an on-going experimental program to charac-terize the effects of processing errors on kinoform performance.Diffraction efficiency and modulation transfer function data aregiven for various types of processing errors present in staircasekinoforms of a f/10 Fresnel phase lens having two and four 1ev-els. Processing errors include etch depth, linewidth, and maskalignment. Processing errors, especially mask alignment, areshown to have the greatest impact on diffraction efficiency andvery little effect on image quality.1. INTRODUCTIONThe use of lithographic and etching techniques to fabricatekinoforms was first demonstrated by d'Auria et a11 and has nowbecome very popular following the great improvements in thetechnology driven by the microelectronics industry. In the usualapproach described by Veldkamp and Swanson2, a staircase approxi-mation to the ideal continuous phase profile is implemented inthe substrate using a binary mask-and-etch sequence in which thenumber of phase levels generated is a power of two. Kinoformperformance is usually discussed in terms of diffraction effi-ciency and image quality, and Dammann3 first showed how to calcu-late diffraction efficiency for the staircase structures usingthe Fourier theory. Subsequently, Petit et al.4 and Gaylord andMoharam5 applied rigorous vector-field theory to calculate theefficiency of general periodic structures and treated the stair-case profiles as special cases. Image quality, for those kino-forms which form images, has been modeled either using raytracecodes with an infinite index approximation6'7'8 or using brute-force integration of the scalar Kirchhoff equation8'9.In all of the cases cited above, kinoform performance was calcu-lated only for geometrically perfect profiles without consideringthe unavoidable effects of processing errors. Such predictionsthus represent an upper limit on the performance expected forreal kinoforms. The effects of processing errors on diffractionefficiency have been investigated both theoretically and experi-mentally by the authors10, and an independent theoretical treat-ment has been given at the same time by Farn and Goodman11. Thekinoforms in both cases were the staircase type. Cox et al.'°showed conclusively that mask alignment error was the most sig-1W

We examine the role of processing errors on diffraction efficiency of binary optical elements and the validity of the Fourier model to predict diffraction efficiency. We show that mask alignment error can significantly degrade efficiency. Models based on the Fourier theory can adequately predict both the magnitude of diffraction efficiency and its sensitivity to processing errors for optically slow elements (f/b). For optically fast elements (

The transition from a positive to a negative temperature coefficient of resistivity (TCR) has been studied in the artificially layered metallic system Nb-Cu. We find the TCR to undergo a rather sudden change in sign from positive to negative as the layer thickness is decreased below approximately 10 A. The temperature dependence of the conductivity in the nonmetallic regime can be explained by localization-type theories, and implies that both localization and Coulomb effects are important in this purely metallic three-dimensional system.