Abstract: An electro-optical device having six image signal lines that are third layer leads comprising the same layer as data lines. A lead which is branched from one image signal line and crosses the other image signal lines is a parallel connection of a first layer lead and a second layer lead. The first layer lead comprises the same layer as the scanning lines in a display region and the second layer lead comprises the same layer as a barrier film of a thin film transistor (TFT) in the display region. Although the first and second layer leads have high resistance alone, the parallel connection can reduce resistance. In other portions, the second layer lead is used alone to improve the design versatility. Thus, the design versatility of peripheral circuits such as a sampling circuit in an electro-optical device is improved and the lead resistance in the peripheral circuit is reduced.

Abstract: An improved electro-absorption semiconductor modulator using an external modulation, in which a multi-quantum well (MQW) structure for absorbing a light beam is provided to increase an optical absorption capability according to an electric field, thus increasing an optical power difference between ON and OFF states. Accordingly, the electro-absorption semiconductor modulator includes a semiconductor substrate; a lower cladding layer deposited over the semiconductor substrate; a multi-quantum well (MQW) layer comprised of barrier layers and undoped well layers stacked, in succession, predetermined times on the lower cladding layer, the barrier layers being doped with an impurity; an upper cladding layer deposited over the multi-quantum well layer; and, an ohmic contact layer deposited over the upper cladding layer. The impurity comprises an n-type dopant such as silicon and has a doping density of 1017/cm3.

Abstract: A light modulator having a reduced parasitic static capacitance includes a semiconductor substrate having a mesa section and a bonding pad forming section formed thereon. A primary insulating film is formed on the substrate so as to continuously cover the mesa section and the bonding pad forming section. After a mask has been formed on a portion of the primary insulating film that is above the bonding pad forming section, the remaining portion of the primary insulating film is etched off, followed by removal of the mask. After the removal of the mask, a secondary insulating film is formed so as to continuously cover that portion of the primary insulating film above the bonding pad forming section and the mesa section so that a relatively thick insulating layer can be formed only above the bonding pad forming section.

Abstract: A light modulating or switching array (10) having a plurality of discrete protrusions (16) formed of electro-optic material, each of which is electrically and optically isolated from each other. The protrusions (16) have defined a top face (20), a bottom face (30), first and second side faces (22, 24), and front and back faces (26,28). There are a plurality of electrodes (34) associated with each of the protrusions (16), these electrodes (34) being capable of inducing an electric field in the electro-optic material for independently modulating a plurality of light beams which are incident upon one of the faces (20, 22, 24, 26, 28, 30) of the protrusions (16). The electro-optic material may be of PLZT, or a member of any of the groups of electro-optic crystals, polycrystalline electro-optic ceramics, electro-optic semiconductors, electro-optic glasses and electro-optically active polymers.

Abstract: A Bragg modulator modulates the intensity of a light beam, in particular of a laser beam. The Bragg modulator includes an electro-optic crystal wafer with a rectangular top face, in particular a lithium niobate or lithium tantalate crystal wafer, and a grid structure with normal zones and inversion zones. In the inversion zones, the direction of the spontaneous polarization is inverted compared to a normal direction in the normal zones. Electrodes are disposed on the top and bottom faces of the crystal wafer to generate an electric field therebetween. The grid structure is spaced apart from the front, back and side faces of the crystal wafer and is completely covered by the electrodes. The inversion zones of the grid structure are disposed at the Bragg angle (&THgr;B) relative to the direction of a light beam entering the front face of the crystal wafer. The entire grid structure is positioned such that the refracted light beam exits the crystal wafer on its rear face.

Abstract: A picture display device in accordance with the present invention is provided with a light guiding member equipped with a total reflection surface capable of transmitting an incoming light ray for image display by means of total reflection, and an optical switching member having a micro prism that extracts evanescent light leaking out of the total reflection surface and reflects it to a display area of the total reflection surface. The incoming light ray is applied to the display area from two symmetric directions so as to obtain outgoing light rays from all surfaces of the micro prism. Hence, a picture display device featuring still higher brightness and higher contrast can be attained. Furthermore, an apex angle of the micro prism, etc. are optimized thereby to provide further uniform outgoing light arranged perpendicularly with respect to the total reflection surface, thus realizing a picture display device capable of displaying high-quality images.

Abstract: A light modulation system, wherein a light source provides light of a certain wavelength to be modulated by a material layer, which forms part of a specifically configured plate assembly. The modulation layer is placed in the optical path of the light source. Further, the modulation layer is switched between first and second states, and cooperates with the light source to produce a train of pulses at a given pulse rate. The resulting optical pulses transmitted through the modulation layer are converted from the original certain wavelength to a lower wavelength by a frequency converting device.

Abstract: A ferroelectric liquid crystal display panel comprises an addressable matrix of pixels and an arrangement for selectively addressing each pixel within a series of addressing frames in order to vary the transmission level of the pixel relative to the transmission levels of the other pixels. The addressing arrangement utilizes a temporal dither (TD) addressing scheme for addressing each pixel within each frame with different combinations of temporal dither signals applied to separately addressable temporal bits within the frame to produce different overall transmission levels.

Abstract: An optical modulator controllably attenuates an optical signal by changing the index of refraction of an electro-optic prism in the modulator by varying the electrical bias applied to the electro-optic prism. Changing the index of refraction alters the path along which the optical signal travels through the optical modulator. By appropriately focusing the optical signal, the location of the optical signal relative to an output fiber can be controlled to vary the degree of optical coupling between the optical signal and the output fiber, thereby changing the amplitude of the outgoing optical signal. In one embodiment, the optical modulator has an electro-optic prism located between a lens and a mirror, where the mirror reflects the optical signal to pass through the prism and the lens two times: once along an input path and once along an output path.

Abstract: A light modulating device, is provide, which includes a first set of fibers and a second set of fibers being arranged to form a two dimensional array of junctions between fibers of the first set of fibers and fibers of the second set of fibers. Each of the fibers of the first and second sets of fibers includes a longitudinal conductive element, whereas fibers of at least one of the first and second sets of fibers, at least at the junctions, further include a coat of an electro-optically active substance being capable of reversibly changing its optical behavior when subjected to an electric or magnetic flux or field. The light modulating device has advantages over prior art light modulating devices because it is (i) readily fabricated in any desired dimensions; (ii) flexible; (iii) foldable/collapsible; (iv) simple to manufacture; and therefore (v) cost-effective.

Abstract: A display device including an illuminating source which emits radiation and a spatial light modulator illuminated by the radiation. The modulator includes a matrix of N.times.M elementary pixels (X.sub.i,j) of dimensions d.sub.N .times.d.sub.M, the pixels X.sub.i,j and X.sub.1+i,j being separated by a spacing p.sub.N. The radiation is collimated in each pixel. The spacing p.sub.N is greater by at least an order of magnitude than the dimension d.sub.M. The display may be used as a flat television screen.

Abstract: Generally speaking, in accordance with the invention, an optical transmission modulation apparatus is provided for modulating light transmitted through the apparatus. The apparatus comprises a metal film having a periodic array of subwavelength-diameter holes provided therein, and a supporting layer. At least a portion of the supporting layer has a selectively variable refractive index, the selectively variable refractive index portion being substantially adjacent to the metal film such that the metal film and the supporting layer form a perforated metal film unit. Selective variation of the refractive index of the selectively variable refractive index portion modulates the intensity of the light transmitted through the perforated metal film unit without substantially changing the direction of the light. Flat panel displays, spatial light modulators and tunable optical filters based on the optical transmission control apparatus are also provided.

Abstract: An optical switch for switching first and second input beams linearly polarized in the same direction which has a first half wave plate for rotating the polarization optically coupled to the second input beam, the first input beam and the output of the half wave plate input to a first polarization beam displacer which provides a combined beam, the output of which is connected to a controllable half wave gate which in a passive state passes the combined beam gate and in the active state passes the combined beamed rotated by 90 degree to an output Gate in dependence of a controlled signal input to the controllable wave gate. The output of the controllable wave gate is input to a second polarization beam displacer which refracts light into first and second refracted output beams displaced from each other a predetermined distance and a second half wave plate.

Abstract: A multi-gas sensor is provided which modulates a polarized light beam over a broadband of wavelengths between two alternating orthogonal polarization components. The two orthogonal polarization components of the polarization modulated beam are directed along two distinct optical paths. At least one optical path contains one or more spectral discrimination element, with each spectral discrimination element having spectral absorption features of one or more gases of interest being measured. The two optical paths then intersect, and one orthogonal component of the intersected components is transmitted and the other orthogonal component is reflected. The combined polarization modulated beam is partitioned into one or more smaller spectral regions of interest where one or more gases of interest has an absorption band.

Abstract: An electro-optic modulator is described which uses periodic inverted domain regions to permit it to be able to handle high powered optical light.

Abstract: A method for mechanically stabilizing and for tuning a filter having a photonic crystal structureThe cavities of the filter fabricated as a photonic crystal structure are filled with optically transparent material having an adjustable refractive index. The optical properties of the filter and, thus, the filtering action are adjusted by way of an electric field having a variable field strength.It is possible to produce small-dimensioned, narrow-band filter elements, which are finely tunable and tunable within a broad range, and to realize them as filter elements which are integrated with a high packaging density.

Abstract: A plasma addressed electro-optical display device having a plasma cell comprising an anode electrode and a cathode electrode arranged in parallel in a plasma chamber in which a discharge is performed and a liquid crystal cell arranged near the plasma chamber and driven through a virtual electrode formed in the region discharged in the plasma cell, wherein as the discharge gas sealed in the plasma chamber, use is made of one of the group of approximately 100 percent by volume of xenon (Xe); approximately 100 percent by volume of krypton (Kr); a mixed gas of xenon (Xe) and an inert gas other than xenon (Xe) or a stable gas; and a mixed gas of krypton (Kr) and an inert gas other than krypton (Kr) or a stable gas.

Abstract: A wideband quasi-optical millimeter-wave resonator achieves a wideband frency operation by using a variable dielectric constant photoconducting lens in a Fabry-Perot resonator. Changing the dielectric constant of the lens creates an associated change in the resonant frequency for a given axial mode.

Abstract: A switchable optical birefringent filter for polarized light incident thereon includes first and second retarder networks in optical series and a switch associated with at least one of the first and second retarder networks for selectively altering one of the polarization state and the angular orientation of the polarization state relative to the angular orientation of the second network, of light as it is received by the second network. In one operating mode, the filter produces a spectral filtration of light passing through the filter and in another mode transmits all light within a specified range of wavelengths without significant alteration.

Abstract: There is disclosed a reshaping device for optical short pulses to effectively perform reshaping of and eliminate noise from an optical short pulse of a pulse width of pico second order less than a carrier life time. Input optical short pulses are applied to a saturable absorption element, while an assist light of a wavelength longer than that of the input optical signal pulses is also applied to the saturable absorption element to accelerate, by stimulated emission, recombination of excited electrons and holes produced in the saturable absorption element in response to the input optical signal pulses, so that the input optical signal pulses reshaped are derived from the saturable absorption element.

Abstract: The use in an electro-optical modulator of an electro-optical crystal in the form of a solid-solution compound of formula (NH.sub.4).sub.x Rb.sub.1 -.sub.x H.sub.1 -.sub.y D.sub.y SeO.sub.4, x and y being concentration coefficients varying from 0 to 1, (crystals of hydrogenated or deuterated rubidium or ammonium selenates) in order to modify the polarization, the phase or the intensity of an incident light beam, using a small control voltage.

Abstract: A method and apparatus for modulating light, wherein a light source provides light of a certain wavelength to be modulated by a layer of superconducting material which forms part of a specifically configured plate assembly. The superconducting layer is placed in the optical path of the light source. Further the superconducting layer is switched between a partially transparent non-superconducting state and a substantially non-transparent superconducting state by a modulation circuit. The resulting optical pulses transmitted through the superconducting layer are converted from the original wavelength to a lower wavelength by a frequency converting device.

Abstract: An excited state polarization altering optical filter includes a vapor cell having a population of electrons with a plurality of energy levels that receive light and transmit light according to the received light. A first pulsed dye laser applies a beam of light by way of a circular polarizer to provide a first beam of light having a first polarization to the vapor cell. The first beam of light causes transitions of the electrons from one energy level to another energy level. A second pulsed dye laser applies a second beam of light with a second, differing, linear polarization to the vapor cell. The vapor cell differentially transmits the first and second beams of light in accordance with the differing polarizations. A delay path is provided for delaying the second beam of light before the second beam of light is applied to the vapor cell. The delay path is tuned by adjusting the length. A third laser applies a beam of light to the first and second lasers. The third laser may be an Nd:YAG laser.

Abstract: Method for optical energy transfer and energy guidance uses an electric field to control energy propagation using a class of poled structures in solid material. The poled structures, which may form gratings in thin film or bulk configurations, may be combined with waveguide structures. Electric fields are applied to the poled structures to control routing of optical energy. Techniques include frequency-selective switchable- and adjustable-tunable reflection, splitting, directional coupling, frequency-tunable switching and efficient beam combining, as well as polarized beam combining. Adjustable tunability is obtained by a poled structure which produces a spatial gradient in a variable index of refraction along an axis in the presence of a variable electric field. In one embodiment, the present invention is a method of switching a grating which consists of a poled material with an alternating domain structure of specific period.

Abstract: Novel optical modulators and other high performance Faraday-Stark magneto-optoelectronic devices (MOE's) are disclosed that allow electrical adjusting of the polarization (or other optical properties) of an excitation light at high modulation bandwidth and deep modulation depths through the Faraday-Stark effect. The high performance Faraday-Stark magneto-optoelectronic devices of the present invention include a Faraday-Stark cell having at least one quantum well formed in a semiconductor or other material defining transition energies and wavefunction overlaps that correspond to the presence and/or magnitude of magnetic and electric fields that may be present to the quantum wells of the cell.

Abstract: A spatial light modulator having a photoconductor, a matrix of reflectors and a modulating layer is disclosed. The portions of the photoconductor in between the reflectors have a smaller photoconductivity than those portions under the reflectors. The reduced photoconductivity can be made, for example, by doping the photoconductor while using the reflectors as a mask or by illuminating the photoconductor with a light of 360 joules/cm.sup.2. The photoconductor in between the reflectors may be grooved, The photoconductor can be a superlattice photoconductor.

Abstract: A high-resistance compound semiconductor 12 is epitaxially grown on a low-resistance compound semiconductor 11 and a dielectric reflecting film 13 is formed thereon, thereby forming a monolithic sensor 10. As the low-resistance compound semiconductor 11, a compound semiconductor is used which has a large bandgap so as to enable probe light to pass therethrough without being absorbed and which has a lattice constant and a thermal expansion coefficient, which are close to those of the high-resistance compound semiconductor. In addition, since the low-resistance compound semiconductor 11 also serves as an electrode, a compound semiconductor which has a resistivity of 10.sup.+1 .OMEGA.cm or less is used. Since the shorter the wavelength of the probe light used, the larger the retardation change and the larger the signal output, a compound semiconductor which has a large bandgap is used as the high-resistance compound semiconductor 12 so that light of short wavelength can be used.

Abstract: A high-resistance compound semiconductor 12 is epitaxially grown on a low-resistance compound semiconductor 11 and a dielectric reflecting film 13 is formed thereon, thereby forming a monolithic sensor 10. As the low-resistance compound semiconductor 11, a compound semiconductor is used which has a large bandgap so as to enable probe light to pass therethrough without being absorbed and which has a lattice constant and a thermal expansion coefficient, which are close to those of the high-resistance compound semiconductor. In addition, since the low-resistance compound semiconductor 11 also serves as an electrode, a compound semiconductor which has a resistivity of 10.sup.+1 .OMEGA.cm or less is used. Since the shorter the wavelength of the probe light used, the larger the retardation change and the larger the signal output, a compound semiconductor which has a large bandgap is used as the high-resistance compound semiconductor 12 so that light of short wavelength can be used.

Abstract: Apparatus for rotating polarization of polarized light includes an input of linearly polarized light, a variable retarder for retarding the phase of one quadrature component of such linearly polarized input light an amount relative to the phase of the other quadrature component, and an analyzer for converting such quadrature components to linearly polarized light having a plane of polarization that is a function of the amount of such phase retardation. By changing the electrical input to the retarder the amount of rotation can be altered.

Abstract: Integrated electrooptic modulator and process for the production thereof. This modulator comprises a substrate (2), a guide structure having a guiding layer (14) defining a microguide (16) for the propagation of beams, interposed between the lower and upper layers (12, 18) having indices below that of the guiding layer, a cavity (20) made in the upper layer, an active material such as an active, solid, organic polymer (26), whose index can be electrically modified and which fills the cavity and serves as an optical guide, a confinement layer (28) covering the polymer and the guide structure, the indices of the upper layer and the confinement layer being below that of the polymer, two electrodes placed on either side of the polymer, an electrode (6) being positioned between the lower layer and the substrate and the other electrode (30) is located on the confinement layer.

Abstract: An optical filter device comprised of two parallel arrays of lenses. Each lens in the first array faces a lens in the second array to form a pixel. Lens pairs in a pixel are separated by the sum of their focal distances and include in their common focal surface a "smart" layer for modulating light passing through the focal surface. Preferred embodiments include car rear view mirrors, sunglasses, glasses for night driving, laser goggles, nuclear goggles, sun visors, sun shields, windshields, space suit helmet visors, optical instrument protection devices, window filters and energy conservation devices.

Abstract: An image processing apparatus comprises a liquid modulator having a photoconductive material including an image-writing plane, a liquid crystal layer laminated on the photoconductive material, a pair of electrodes sandwiching the photoconductive material and the liquid crystal layer, and a spacer inserted between the photoconductive material and one of the electrodes. Also provided are an analog writing system for analogously writing an original image in the light modulator; a digital reading system for digitally reading the image written in the light modulator; a processing section for image-processing the read image data; a digital writing system for digitally writing processed image data in the light modulator; and, an analog reading system for analogously reading an image written in the light modulator. The liquid crystal layer is either a phase-transition type liquid crystal, a p-type smectic A liquid crystal providing a storage function, or a ferroelectric liquid crystal providing a storage function.

Abstract: An optical shutter device for use, e.g., in an optical printer includes a plurality of electrooptic chips each having a plurality of very small segments for optical modulation. The optical shutter device has a voltage adjusting circuit which individually supplies the driving voltage to the chips depending on the light transmitting characteristics intrinsic to the chips. Thus, even when the chips have different light transmitting characteristics, the image produced by the chips will have a uniform intensity.

Abstract: A cinematographic system records motion-picture images on an elongate information recording medium which includes either a charge storage layer or a light modulating layer. The recorded images are reproduced and projected onto a screen. If the charge storage layer is employed, the motion-picture images are recorded as corresponding electric charge images photoelectrically converted from optical images, and if the light modulating layer is employed, image information corresponding to the motion-picture images is recorded under an electric field depending on electric charge images photoelectrically converted from optical images.

Abstract: An image processing apparatus includes a light modulator, an analog writing system for analogously writing an image of an original in the light modulator, a digital reading system for digitally reading the written image out of the light modulator, a processing section for processing the read image data, a digital writing system for digitally writing the processed image in the light modulator, and an analog reading system for analogously reading the image written on the light modulator. The light modulator includes a photoconductive material, a liquid crystal layer laminated on the photoconductive material, and a pair of electrodes sandwiching the photoconductive material and the liquid crystal layer. The liquid crystal layer can provide a storage function so as to enable the reading and writing of the image from the same direction.

Abstract: An optical modulation apparatus includes a semiconductor element having a quantum well structure, a unit for applying an electric field to the quantum well structure of the semiconductor element, a unit for supplying polarized probe light to the semiconductor element, the probe light emerging from the semiconductor element such that a polarization state thereof is changed by an electrooptical effect in the quantum well structure, a unit for causing the semiconductor element to receive pump light which causes virtual charge excitation in the quantum well structure, the virtual charge excitation screening the electric field applied to the quantum well structure, and a polarizer for converting a change in polarization state of the light emerging from the semiconductor element into a change in intensity.

Abstract: A charge latent image recording medium includes an electrode, a dielectric member, a member suppressing a transfer of charges, and a photoconductive member laminated in the order without any gaps therebetween. A system for reading a charge latent image recorded in a recording member includes means for projecting a first electromagnetic radiation beam along a path extending to the recording member, means projecting a second electromagnetic radiation beam approximately along the path for reading the charge latent image, guiding means disposed in the path changing electric resistance thereof along the path threthrough, in response to the first electromagnetic radiation beam projected thereto, for guiding an electric field of charges of the charge latent iamge.

Abstract: An optical logic operation apparatus includes an optical induction refractive index crystal having first and second planes parallel to each other and a device for inputting a coherent probe light from the first plane of the crystal. At least one of the first light output from the first plane of the crystal and the second light output from the second plane of the crystal is taken out so that one of the first and second lights is amplified by the two-wave coupling of the probe light reflected by the second plane and the probe light inputted from the first plane and the other light is attenuated likewise by the two-wave coupling. The inputted image is projected onto the crystal by use of light incoherent to the probe light. With the incidence of the incoherent light, a gain distribution corresponding to the inputted image is generated in the crystal so as to modulate the first and second lights spatially.

Abstract: A color imaging system for use as an electronic still camera, for example, includes a color separator for separating the optical image of a subject from a lens into a plurality of different color images, an optical shutter selectively openable for transmitting the optical image of the subject to the color separator, a photoconductive layer for converting the different color images into respective electric charge images, and an information recording medium for recording images corresponding to the electric charge images under an electric field developed between the photoconductive layer and the information recording medium. The timing with which the optical shutter is opened and the timing with which the electric field is generated by the power supply, are controlled by a control unit depending on imaging conditions selected by the user. The color imaging system also has an optical viewfinder for allowing the user to visually observe the optical image of the subject introduced by the lens.

Abstract: A recording apparatus comprises first electrode, color-separation filter, recording, carrier generation, carrier transport, and second electrode layers which are laminated in order of mention. The recording layer and carrier generation layer may be separated at a given space. The recording layer comprises carrier retaining layer or a photo-modulation layer. Light image from an object is projected on the carrier generation layer through the first electrode, color-separation, and recording layers via an object lens enters the carrier generation layer. Carrier generated in the carrier generation layer in response to the light image are transported to the second electrode in response to application of a given voltage between the first and second electrodes. Discharge caused by application of the given voltage transfers a latent carrier image to the recording layer. The first electrode, color-separation filter and recording layers may be used for recording medium.

Abstract: A photo-to-photo transducer is composed by laminating a photoconductive layer member and a photo-modulation layer member including liquid crystals of scattering type each other and disposing the members between two transparent electrodes. The transducer is operated as follows: a specified voltage is applied across the electrodes to operate the photo-modulation layer member in the vicinity of operation threshold level thereof; an electro-magnetic radiation beam for writing information is projected onto the photoconductive layer member through the electrode at the side thereof; and an electro-magnetic radiation beam for reading the information is projected onto the photo-modulation layer member through the electrode at the side thereof, thus the electro-magnetic radiation beam for reading the information is modulated accordingly with intensity of the electro-magnetic radiation beam for writing the information.

Abstract: An optical switch comprises a substrate, a lower cladding layer, a waveguide layer, and an upper cladding layer each formed of a semiconductor, and in which at least one of the three layers except the substrate has a quantum well structure at a quantum confined potential. The well plane of the quantum well structure is symmetrical with respect to the center position thereof, and varies in proportion to the square of the distance from the center position. If an electric field is applied perpendicular to the well plane, the respective changes in the absorption coefficient and refractive index in the vicinity of the absorption edge are influenced by absorption peak shifts attributable to both 1e-1hh and 1e-11h transitions. Thus, the optical switch operates in response to both TE and TM mode light without depending on polarization.

Abstract: A harmonics generation element which comprises a nonlinear optical element having single-crystals of lithium niobate containing magnesium of less than 5 atomic per cent. The nonlinear optical element has 3 ppm or less of impurity Fe and is configured so that a primary laser beam is made incident into the nonlinear optical element and a secondary output light having a wavelength of higher-order harmonics is emitted therefrom.

Abstract: An apparatus for processing information carried by an electro-magnetic radiation beam. The apparatus includes a charge holding member for storing a charge latent image, a generator for generating an electro-magnetic radiation beam which is a superimposition of a plurality of electro-magnetic radiation beams with different wavelength ranges, a filter for separating the superimposed beam into the plurality of electro-magnetic radiation beams and a photo-conductive member provided adjacent to the charge latent image holding member and having an impedance which varies according to the intensity of each of the plurality of beams separated by the filter. Charge latent images corresponding to each of the plurality of beams are thus recorded on the charge latent image holding member. The charge latent images thus recorded on the charge latent image holding member are reproduced by means of a photo-modulation member provided instead of a photo-conductive member.

Abstract: An optical modulation method and apparatus uses superconductive oxide material for the optical modulation element. The current, magnetic field, temperature or pressure applied to the superconductive oxide material is varied so as to induce a superconduction-normalconduction transition, and the resulting variation in optical characteristics such as the reflectivity, transmissivity or refractive index of the superconductive oxide material modulate the input light. The method and apparatus are fast in operation and simple in structure. The method and apparatus also detect the variation in the current, magnetic field, temperature or pressure as a change in the reflectivity, transmissivity or refractive index of the superconductive oxide material on the basis of a superconduction-normalconduction transition.

Abstract: A device structure is provided for optical modulation using a quantum interference effect in an excited state of electron-systems. The optical modulation is performed by causing the effect of modulation on the excited state of electron-systems represented by excitons to be executed on light via the state in which the light and the excited state of electron-systems represented by the excitonic polaritons are coupled.

Abstract: There is provided a recording medium for recording information in a form of a charge latent image. The recording medium comprises, at least, an electrode through which an electro-magnetic radiation beam passes, a photo-conductive layer (hereinafter abbreviated in a PCL) whose resistance varies when the beam is applied thereto and an insulation layer (hereinafter abbreviated in an IL), the electrode and the layers being laminated to each other. There is further provided an apparatus for recording an image as a charge latent image on the medium described above. The apparatus comprises a guide for guiding an electro-magnetic radiation beam through the electrode, an auxiliary electrode arrangeed to face the madium so as to interpose the PCL and the IL between the electrodes and an unit for applying an electric field across the electrodes. There is still further provided an apparatus for reproducing information prerecorded as a charge latent image on the medium.

Abstract: A voltage in a selected area of an object is measured by launching an input light beam into an electrooptic material whose refractive index is changed in accordance with an electric field created by the voltage in a selected area of an object to be measured, and detecting a change in polarization or in a deflection angle of an output light beam from the electrooptic material. A medium having a dielectric constant greater than the air is placed between the area to be measured and the electrooptic material.

Abstract: An improved optical isolator (6) for a semiconductor laser (2) for use in optical communication systems consists of a polarizer (4) and a birefringent medium (5). An electric field is applied to the birefringent medium (5) via electrodes (7) for varying the indices of refraction of the birefringent medium (5). By the variation of the indices of refraction, the optical isolator (6)can be adapted to different light wavelengths.