Showing papers on "Spatial light modulator published in 1981"
01 Jan 1981
TL;DR: Two-dimensional signal processing (including image processing) is possile, in spite of the inherent one-dimensional nature of the acousto-optic device as a spatial light modulator.
Abstract: The use of acousto-optic devices in real-time signal convolution and correlation has increased dramatically during the past decade because of improvements in device characteristics and implementation techniques. Depending on the application, processing can be implemented via spatial or temporal integration. Two-dimensional signal processing (including image processing) is possile, in spite of the inherent one-dimensional nature of the acousto-optic device as a spatial light modulator.
152 citations
TL;DR: The role of secondary electron emission in the operation of the MSLM is discussed, and design modifications that would yield a spatial resolution of ~10 cycles/mm at the 50% point on an MTF curve are proposed.
Abstract: The microchannel spatial light modulator (MSLM) is a versatile, highly sensitive, and optically addressed modulator that is well suited for low-light level real-time optical information processing. The image processing operations that can be achieved with the MSLM include contrast reversal, contrast enhancement, edge enhancement, image addition and subtraction, analog and digital intensity level thresholding, and binary level logic operations such as AND, OR, EXCLUSIVE OR, and NOR. Several of these operations are demonstrated herein. Recent prototype MSLMs have exhibited a halfwave exposure of 2.2 nJ/cm(2), an optical information storage time of more than two months, and a framing rate of 40 Hz with full modulation depth (200 Hz with 20% modulation depth). The role of secondary electron emission in the operation of the MSLM is discussed, and design modifications that would yield a spatial resolution of ~10 cycles/mm at the 50% point on an MTF curve are proposed.
68 citations
TL;DR: The fabrication and characterization of a 17.5-M bit/sec integrated optical correlator makes use of a novel programmable electrooptic spatial light modulator in conjunction with a digitally modulated surface acoustic wave.
Abstract: The fabrication and characterization of a 17.5-M bit/sec integrated optical correlator are described. The correlator makes use of a novel programmable electrooptic spatial light modulator in conjunction with a digitally modulated surface acoustic wave.
40 citations
Patent•
23 Mar 1981
TL;DR: In this article, a method for coherent detection of modulated optical signals employing optical mask-generated signals is described, where a spatial light modulator modulates a source beam with an information signal composed of one or more frequency components within its frequency bandwidth.
Abstract: A method of and an apparatus for coherently detecting modulated optical signals employing optical mask-generated signals is disclosed. A spatial light modulator modulates a source beam with an information signal composed of one or more frequency components within its frequency bandwidth. The frequency components which are output from the modulator, including the zero frequency component, diverge and become spatially separated. A reference beam is formed from the zero frequency component by a reference beam generator. The reference beam is generated so as to appear to diverge from a reference point located at or near the spatial light modulator. The optical detector performs coherent detection by squaring the sum of the frequency components and the reference beam to provide an output information signal as a function of the input information signal.
25 citations
TL;DR: In this paper, a bistable spatial optical device has been developed on the basis of a spatial light modulator which contains photosensitive and electrooptical liquid crystal layers, where an internal feedback loop is established.
13 citations
TL;DR: The sensitivity of the Prom is low by comparison with other candidate SLMs, its frequency response rapidly decreases with increasing spatial frequency f, and the diffraction efficiency is proportional to l/f with low f and to l-f for high f with a 3-dB point at about 4-5 cycles/mm.
Abstract: Optical data processing systems require 2-D spatial light modulators (SLMs) that are capable of converting an input optical (or electrical) signal in real-time into a transparency suitable for spatial modulation of a collimated laser beam. These devices must operate in real-time and be reusable. A well-documented candidate SLM is the Prom. It uses a bismuth silicon oxide (BSO) crystal that is both photoconductive and electrooptic. In operation, the Prom is illumi nated with white light of wavelength λw (350–450 nm). The spatial intensity distribution of this λw light is converted to a spatial charge pattern in the BSO. When read out with light of wavelength λR (633 nm usually), the amplitude of the readout beam is spatially modulated corresponding to the intensity modulation present on the λw light pattern. In the Prom, modulation of the ΛR light occurs by the lon gitudinal electrooptic effect (the direction of light propagation and the applied electric field are colinear). A [100] cut BSO crystal is used to optimize the corresponding electrooptic tensor coefficients for the longitudinal electrooptic effect. The sensitivity of the Prom is low by comparison with other candidate SLMs. Furthermore its frequency response rapidly decreases with increasing spatial frequency f. The diffraction efficiency is proportional to l/f with low f and to l/f for high f with a 3-dB point at about 4-5 cycles/mm.This performance occurs because the spatial charge layer in duced in the Prom by the λw light lies within the volume of
9 citations
TL;DR: A multistable spatial optical device has been developed on the basis of a spatial light modulator which contains photosensitive and electrooptical liquid crystal layers where an internal feedback loop is established as mentioned in this paper.
9 citations
TL;DR: An integrated optics spectrum analyzer based on using the linear electrooptic effect is investigated, and questions concerning efficiency, dynamic range, design, and implementation are discussed.
Abstract: An integrated optics spectrum analyzer based on using the linear electrooptic effect is investigated. This spectrum analyzer performs Fourier analysis of sampled electronic signals, where each signal is fed to an electrode of an electrode array. The electrode array acts as a spatial light modulator, and the diffracted light field, representing a weighted discrete Fourier transform (DFT), is focused on a detector array by an integrated transform lens. The theory of operation of the spectrum analyzer is outlined, numerical results relating to this theory are presented, and questions concerning efficiency, dynamic range, design, and implementation are discussed.
7 citations
01 Dec 1981
TL;DR: A sensitive, high-speed, optically addressed spatial light modulator is being developed for real-time optical dataprocessing applications involving low-level-control light signals, and preliminary results are reported.
Abstract: The Microchannel Spatial Light Modulator (MSLM), a versatile, highly sensitive, and optically addressed device being developed for real time optical information processing is discussed. The MSLM operates by converting an input optical image into a charge distribution at the surface of an electro-optic crystal. The charge distribution generates an electric field which modulates the refractive index of the crystal and thereby the phase or intensity of an image readout beam. Prototype devices employing 250 micron thick crystals exhibited a spatial resolution of 5 cycles/mm at 50% contrast, an exposure sensitivity of 2.2 nJ/cu cm and framing rates of 40 Hz with full modulation depth. The image processing operations that have been achieved using the internal processing mode of the MSLM include contrast reversal, contrast enhancement, edge enhancement, image addition and subtraction, analog and digital intensity thresholding, and binary level logic operations such as AND, OR, EXCLUSIVE OR, and NOR.
2 citations
TL;DR: In this paper, a theoretical study of the process of writing a single line on a target of an electron-beam spatial light modulator operating in the equilibrium data-recording regime is made.
Abstract: A theoretical study is made of the process of writing a single line on a target of an electron-beam spatial light modulator operating in the equilibrium data-recording regime. The amplitude-frequency characteristic of the modulator is derived. It is shown that the resolution in the regime of equilibrium recording of the potential is higher than in the nonequilibrium case.
1 citations
Journal Article•
15 May 1981
TL;DR: The Microchannel Spatial Light Modulator (MSLM) as discussed by the authors is an optically-addressed modulator that is well suited for low-light-level, real-time, optical information processing.
Abstract: The Microchannel Spatial Light Modulator (MSLM) is a versatile, highly-sensitive and optically-addressed modulator that is well suited for low-light-level, real time, optical information processing. It consists of a photocathode, a microchannel plate, a planar acceleration grid, and an electro-optic plate in proximity focus. The image processing operations that can be achieved with the MSLM include contrast reversal, contrast enhancement, edge enhancement, image addition and subtraction, analog and digital intensity level thresholding, and binary-level logic operations such as AND, OR, EXCLUSIVE OR and NOR. Recent prototype MSLMs have exhibited a half-wave exposure sensitivity of 2.2nJ/cm2, an optical information storage time of more than two months, and a framing rate of 20 Hz with full modulation depth (100 Hz with 20% modulation depth). The materials and device parameters that limit the ultimate performance of the modulator are discussed.© (1981) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.