Showing papers on "Spatial light modulator published in 1988"
Patent•
28 Oct 1988TL;DR: In this paper, a deflectable beam spatial light modulator formed from a structure of a reflecting layer on a spacer layer, typically photoresist, which in turn is on a substrate containing electronic addressing circuitry is disclosed.
Abstract: A deflectable beam spatial light modulator formed from a structure of a reflecting layer, typically metal, on a spacer layer, typically photoresist, which in turn is on a substrate containing electronic addressing circuitry is disclosed. Also, the method of fabrication including a plasma etch after dicing of the substrate into chips is disclosed.
685 citations
Patent•
22 Jun 1988TL;DR: In this article, a crossbar switch with bifurcated optical fibers (200) having equivalent ends connected to transmitters and receivers (261,..., 264) and single ends in a linear array (245) that is adjacent to a linear micro lens array (240) and a linear spatial light modulator (230) is described.
Abstract: A crossbar switch (200) with bifurcated optical fibers (271, . . . , 286) having equivalent ends connected to transmitters (251, . . . , 254) and receivers (261, . . . , 264) and single ends in a linear array (245) that is adjacent to a linear micro lens array (240) and a linear spatial light modulator (230) with light emitted from a single end reflected back into the single end for undeflected pixels in the spatial light modulator (230) and lost for deflected pixels.
252 citations
TL;DR: In this article, a new type of electron-beam-addressed spatial light modulator has been demonstrated, based on the local tuning of an optothermal nonlinear interference filter by the scanned electron beam.
Abstract: A new type of electron-beam-addressed spatial light modulator has been demonstrated. It is based on the local tuning of an optothermal nonlinear interference filter by the scanned electron beam. Such an e-beam-tunable interference filter device should find applications in both display technology and optical data processing.
134 citations
TL;DR: Modulation at video frame rates has been achieved, providing real-time displays in coherent light, which may be useful for a variety of optical processing and computing applications.
Abstract: Some of the optical characteristics of a recently developed solid-state deformable-mirror spatial light modulator have been investigated. The device is composed of an array of 128 × 128 pixels, with each pixel consisting of four hinged reflective rectangular surfaces. Modulation at video frame rates has been achieved, providing real-time displays in coherent light, which may be useful for a variety of optical processing and computing applications.
77 citations
TL;DR: In this paper, a recently fabricated spatial light modulator incorporating amorphous silicon as the photoconductor and a chiral smectic liquid crystal as the modulating medium is reported.
Abstract: Results are reported for a recently fabricated spatial light modulator incorporating amorphous silicon as the photoconductor and a chiral smectic liquid crystal as the modulating medium. Initial results at room temperature include an MTF of 70 LP/mm at 10% modulation with an operational frequency greater than 1 kHz.
57 citations
TL;DR: Using a 6 X 6 array of integrated quantum-well self-electro-optic-effect devices, an optically addressed spatial light modulator able to convert a visible, incoherent image into coherent infrared (IR) light is demonstrated.
Abstract: Using a 6 × 6 array of integrated quantum-well self-electro-optic-effect devices, we demonstrate an optically addressed spatial light modulator able to convert a visible, incoherent image into coherent infrared (IR) light Depending on the IR wavelength used, the output is either a positive, binary-thresholded version of the input (bistable mode) or its linear, negative (self-linearized) mode This device can also function as a dynamic bistable memory that can retain its internal state without power for times as long as 30 sec
45 citations
TL;DR: These results demonstrate the basic capabilities of the DMD in an image correlator system which, in combination with the potential 8-kHz frame rate for 128 x 128 DMDs, can constitute a very high speed pattern recognition system.
Abstract: Attention is given to experimental results for a binary phase-only filter implementation's correlation operations, using the deformable mirror device (DMD) spatial light modulator as the Fourier plane filter. These results demonstrate the basic capabilities of the DMD in an image correlator system which, in combination with the potential 8-kHz frame rate for 128 x 128 DMDs, can constitute a very high speed pattern recognition system. The DMD has the further capability of operating in the analog mode.
33 citations
Patent•
17 Jun 1988
TL;DR: In this article, a spatial filter with a highly selectable modulation transfer function for processing an image, which may be present in real-time, is presented, where a first optical transmission path receives an image to be processed and optically transmits the image to the spatial filter for processing.
Abstract: An optical image processor utilizes a source of partially coherent light and a spatial filter with a highly selectable modulation transfer function for processing an image, which may be present in real time. The spatial filter contains electro-optic material with electrodes arranged on such material to form a plurality of annular bands of different radii that are concentrically-situated and invididually-addressable. The annular bands are changeable in transmissivity in a continuous spectrum from transparent to opaque in response to an electrical signal on the respective electrodes of the bands. A first optical transmission path receives the image to be processed and optically transmits the image to the spatial filter for processing. A second optical transmission path receives the image processed by the spatial filter and optically transmits the image to an output port. The first and second optical transmission paths may each contain a respective spatial light modulator, whereby, for example, gray scale operations can be performed on the image. Each of the first and second optical transmission paths may include a respective zoom lens, whereby the output image size may be adjusted during image processing without interfering with the operation of the spatial filter. The spatial filter may have a reflective backing on one side for system compactness.
30 citations
Patent•
22 Aug 1988TL;DR: In this article, a spatial light modulator is used to transfer electrical data into an optical form and then employs the photorefractive effect in the bulk for processing the data, which can be used for optical information processing, matrix multiplication, and integrated semiconductor optical information processors.
Abstract: Optical processing using photorefractive GaAs and other compound semiconductor crystals (28) is achieved in a four-wave mixing configuration. Potential applications of optical processing include spatial light modulation, phase conjugation, correlation, convolution, edge enhancement, matrix multiplication, incoherent-to-coherent conversion, and many others. In particular embodiments, optical processing, matrix multiplication, and integrated semiconductor optical information processors are demonstrated. In the case of integration of semiconductors and optical information processors, a spatial light modulator (88) is fabricated on a surface of a compound semiconductor crystal to form an integrated device (86). The device uses the spatial light modulator to transfer electrical data into an optical form and then employs the photorefractive effect in the bulk for processing the data.
26 citations
TL;DR: A spatial light modulator with a thin (1-microm) amorphous silicon (PIN) photoconductor has been demonstrated with a threshold sensitivity of <3 microw/cm(2) and a novel compound electrode design greatly increases the efficiency allowing the use of a photoconductive layer thin enough to achieve good transmission.
Abstract: A spatial light modulator with a thin (1-microm) amorphous silicon (PIN) photoconductor has been demonstrated with a threshold sensitivity of <3 microw/cm(2). A novel compound electrode design greatly increases the efficiency allowing the use of a photoconductive layer thin enough to achieve good transmission. The performance characteristics are reported and compared to the predictions of a theoretical model of the device.
23 citations
TL;DR: The performance of a commercially available liquid crystal TV display was characterized in terms of its modulation depth and optical flatness of the screen was characterized interferometrically, both with and without polarizers, to show the improvement in wavefront quality obtained by replacing the original polarizers.
Abstract: The performance of a commercially available liquid crystal TV display was characterized in terms of its modulation depth. Measurements of screen transmittance and modulation depth, as a function of signal level, showed that the primary limitations of the device as a spatial light modulator were due to the nature of the video scan format and the display drive electronics. The resolution of the device, as measured by the modulation transfer function, is limited more by the physical pixel spacing than by pixel crosstalk. The optical flatness of the screen was characterized interferometrically, both with and without polarizers, to show the improvement in wavefront quality obtained by replacing the original polarizers.
TL;DR: A spatial light modulator is described which consists of a row of 1200 electrostatically deflectable mirror elements that is included in an acoustooptic spectrum analyzer and allows the removal of interfering signals from 333 frequency bands.
Abstract: A spatial light modulator is described which consists of a row of 1200 electrostatically deflectable mirror elements. This deformable mirror device is included in an acoustooptic spectrum analyzer and, as such, allows the removal of interfering signals from 333 frequency bands. Radiometric scans demonstrate the contrast and resolution possible with the device. Based on these results, the suitability of the device to frequency excisors and optical switches is considered.
TL;DR: A real-time polychromatic image correlator that uses a magnetooptic (MO) spatial light modulator (SLM) device for pattern recognition based on both the color and shape of an input object and pattern recognition experiments for naturally illuminated real color objects are presented.
Abstract: A real-time polychromatic image correlator that uses a magnetooptic (MO) spatial light modulator (SLM) device for pattern recognition based on both the color and shape of an input object is presented. The proposed system utilizes a multichannel spectral matched spatial filter employed in a binary coherent optical correlator. Input color images are transformed into binary color coded coherent images by a color grating. The color encoded images are read out by a charge coupled device interfaced with a MO SLM. The color encoded binary images are then processed by a multichannel joint spectral matched spatial filter synthesized by monochromatic light. Pattern recognition experiments for naturally illuminated real color objects are presented.
TL;DR: High contrast ratios are reported with both materials, with the highest value being 45, 000/1.
Abstract: Measurements are reported of the optical transmission and the contrast ratio for single pixel elements of the magnetooptic spatial light modulator consisting of both LLC and GGG materials having antireflection coatings and different thicknesses. The LLC material shows superior transmission values compared with the GGG material. High contrast ratios are reported with both materials, with the highest value being 45,000/1.
04 Feb 1988
TL;DR: In this paper, an NLC photoaddressed spatial light modulator that is faster than twisted-nematic devices has been constructed using the same principle used in this paper.
Abstract: Electra-optic shutters that operate at a kilohertz rate have been demonstrated with nematic liquid crystals operated in the surface-mode or π-cell configuration. This principle has been employed to fabricate an NLC photoaddressed spatial light modulator that is faster than twisted-nematic devices.
Patent•
07 Jun 1988TL;DR: A surface state photodiode is used as the photosensitive element for a Spatial Light Modulator, which includes a liquid crystal layer as discussed by the authors, which provides for a high resolution image and simplicity in manufacture.
Abstract: A surface state photodiode is used as the photosensitive element for a Spatial Light Modulator, which includes a liquid crystal layer. The surface of the photodiode which faces the liquid crystal layer has formed thereon surface states, by means of adsorption of foreign molecules to create a depletion layer, thereby effecting a high dark impedance region. Such a Spatial Light Modulator provides for a high resolution image and simplicity in manufacture.
TL;DR: Theoretical and experimental performance studies are presented showing the results of writing diffraction gratings on the magnetooptic spatial light modulator using a new technique that works well, although it is extremely sensitive to the optical quality of all the components.
Abstract: We present a technique for obtaining improved performance of programmable binary phase-only spatial masks written onto spatial light modulators by suppressing one of the two first-order diffracted beams through spatial dispersion. Theoretical and experimental performance studies are presented showing the results of writing diffraction gratings on the magnetooptic spatial light modulator using this new technique. The method works well, although it is extremely sensitive to the optical quality of all the components.
Patent•
01 Mar 1988
TL;DR: In this paper, an updatable and programmable two-dimensional spatial light modulator, which can be controlled or programmed by addressing it with an optical beam, is used for real-time all-optical multiplication of an n component vector by a large m by m matrix.
Abstract: Real-time all-optical multiplication of an n component vector by a large m by m matrix having digital accuracy utilizes an updatable and programmable two dimensional spatial light modulator, which can be controlled or programmed by addressing it with an optical beam.
TL;DR: In this article, a compact spatial light modulator with optical bistability was constructed with a twisted nematic liquid-crystal layer, a polarizing film, and a Bi12SiO20 crystal layer.
Abstract: A compact spatial light modulator having optical bistability has been constructed with a twisted nematic liquid‐crystal layer, a polarizing film, and a Bi12SiO20 crystal layer. The optical bistability is produced by combining the nonlinear optical transmittance property of the liquid‐crystal electro‐optic light modulator with the photoconductive property of the Bi12SiO20 crystal layer. The device performs optically bistable operations in a controllable manner, and parallel processing of intensity‐level image thresholding is also demonstrated for several threshold levels.
TL;DR: An optical correlator was constructed and tested for use in the data reduction of particle imaging velocimetry photographs, using a 128 x 128-pixel magnetooptic spatial light modulator array as the frequency plane filter.
Abstract: An optical correlator was constructed and tested for use in the data reduction of particle imaging velocimetry photographs. The optical correlator uses a LIGHT MOD, which is a 128 x 128-pixel magnetooptic spatial light modulator array, as the frequency plane filter. Results from both a computer simulation and an experimental optical correlator setup are discussed.
19 Feb 1988
TL;DR: In this article, an optical crossbar switch is proposed which uses a semiconductor-addressed, deformable-mirror spatial light modulator to direct gigabit per second optical transmissions to several receivers.
Abstract: An optical crossbar switch is proposed which uses a semiconductor-addressed, deformable-mirror spatial light modulator to direct gigabit per second optical transmissions to several receivers. The switch performance is described in terms of mirror element size, deflection range and number of modulator elements, as well as emitter, detector and lens dimensions. These parameters are incorporated in a link energy budget and also provide estimates of system dimensions. Maximum-sized 128 to 1000 channel crossbars appear feasible based on the performance of various lightwave components.
22 Aug 1988
TL;DR: In this article, the use of monocrystalline gallium arsenide as a photoaddressing medium for a nematic liquid crystal spatial light modulator was reported with a limiting resolution of 37 1p/mm over a 30mm aperture and a 100Hz frame rate.
Abstract: The use of monocrystalline gallium arsenide as a photoaddressing medium for a nematic liquid crystal spatial light modulator is reported. A GaAs-addressed nematic SLM is demonstrated with a limiting resolution of 37 1p/mm over a 30-mm aperture and a 100-Hz frame rate. The influence of the GaAs thickness on the SLM resolution is analyzed.© (1988) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
22 Aug 1988
TL;DR: In this article, four spatial light modulators (SLM's) with varying efficiency light blocking layers are used to demonstrate the effect of optical isolation on the devices' performance, and it is shown that incorporation of high attenuation blocking layers can improve most aspects of the SLM's behaviour, yielding a 300 fold increase in gain over the device without a blocking layer, and also improving the device resolution to give a 50% MTF at 50 line pairs/mm.
Abstract: Four spatial light modulators (SLM's) with varying efficiency light blocking layers are used to demonstrate the effect of optical isolation on the devices' performance. It is shown that incorporation of high attenuation blocking layers can improve most aspects of the SLM's behaviour, yielding a 300 fold increase in gain over the the device without a blocking layer, and also improve the device resolution to give a 50% MTF at 50 line pairs/mm. A non-ambiguous method of determining the devices sensitivity is also presented along with a simple formula relating the various intensity requirements for a particular application to the gain and light blocking requirements of the SLM.
TL;DR: It is shown that image-coding filters can be easily constructed using the binary phase-only filter and implemented using the Semetex magneto-optic spatial light modulator, and experimental results are presented.
Abstract: We show that image-coding filters can be easily constructed using the binary phase-only filter and implemented using the Semetex magneto-optic spatial light modulator. The theoretical background for such filters is reviewed, and experimental results are presented.
TL;DR: In this paper, the authors demonstrate the operation of a high-speed optically addressed spatial light modulator utilizing a hydrogenated amorphous silicon photosensor and a ferroelectric liquid crystal modulator.
Abstract: We demonstrate the operation of a high-speed optically addressed spatial light modulator utilizing a hydrogenated amorphous silicon photosensor and a ferroelectric liquid crystal modulator. The device has numerous optical parallel processing and interconnect applications. It combines desirable resolution, switching speed, size, and contrast characteristics. The devices are driven by a square-wave voltage, such that read and write operations take place under reverse bias, and an erase operation occurs under forward bias. The capacitance associated with the photosensor plays a critical role in the device performance.
TL;DR: A programmable real-time optical joint transform correlator that generates sharper autocorrelation peaks is presented in this paper, where a microchannel spatial light modulator is utilized as the threshold hard-clipping square-law device.
Abstract: A programmable real-time optical joint transform correlator that generates sharper autocorrelation peaks is presented. A microchannel spatial light modulator is utilized as the threshold hard-clipping square-law device. A liquid crystal television is used to display the input target and reference image. The basic principle of the system and a preliminary experimental result are given.
TL;DR: Holographic optical elements of space-variant impulse response made of dichromated gelatin have been designed and generated using a computerized optical system and experimental performance and characteristics are presented.
Abstract: Holographic optical elements (HOEs) of space-variant impulse response have been designed and generated using a computerized optical system. HOEs made of dichromated gelatin have been produced and used for spatial light modulator defect removal and optical interconnects. Experimental performance and characteristics are presented.
TL;DR: In this article, a real-time broadband pseudocolor image enhancement technique using a liquid crystal television spatial light modulator (LCTV SLM) is described, which is incorporated into a compact white light optical projection system that is able to display, on a large screen, broadband pseudoocolor images of real-world input scenes.
Abstract: A real-time broadband pseudocolor image enhancement technique using a liquid crystal television spatial light modulator (LCTV SLM) is described. Three different schemes to modulate the gray-scale disribution of an input scene by an LCTV SLM through varying the orientations of its analyzer are presented. These schemes are incorporated into a compact white light optical projection system that is able to display, on a large screen, broadband pseudocolor images of real-world input scenes. Experimental results demonstrating the feasibility of the technique are reported.
10 Mar 1988
TL;DR: A novel design concept for a generalized optical crossbar switch that relies on a massive fiber optic logic array and entirely eliminates the need for a spatial light modulator is presented.
Abstract: A novel design concept for a generalized optical crossbar switch is presented. The approach relies on a massive fiber optic logic array and entirely eliminates the need for a spatial light modulator. Interconnection limitations and scaling issues are examined.
Patent•
14 Sep 1988
TL;DR: In this article, a cathode ray tube is used to address a spatial light modulator which includes a photoconductive layer 6, a light blocking layer 7, a dielectric mirror 8 and a liquid crystal layer 8 between transparent electrodes 5, 10.
Abstract: A cathode ray tube 1 is used to address a spatial light modulator which includes a photoconductive layer 6, a light blocking layer 7, a dielectric mirror 8 and a liquid crystal layer 8 between transparent electrodes 5, 10. The image pattern formed in the liquid crystal layer is varied cyclically in dependence upon successive frames of colour information displayed on the phosphor layer 3 of CRT1. These image patterns are read by a light beam whose wavelength (colour) is cyclically selected (eg by an acoustic-optic tunable filter) in synchronism with the cyclically varied image patterns to thereby provide a multi-colour display of variable intensity. This finds particular application in head-up displays for use by pilots of aircraft.