Abstract: A liquid crystal-polymer composite film comprising (1) a high-molecular weight compound containing at least one kind of monomer units providing a side chain having a liquid crystal nature and at least one kind of monomer units providing a side chain having no liquid crystal nature and (2) a low-molecular weight liquid crystal, the high-molecular weight compound (1) and the low-molecular weight liquid crystal (2) being in separate phases, and the monomer units providing a side chain having no liquid crystal nature being crosslinked; and an electro-optical element comprising a pair of substrates each having an electrode having interposed therebetween a liquid crystal-polymer composite film comprising (2) a low-molecular weight liquid crystal and (1) a high-molecular weight compound in separate phases, the substrates each having a surface comprising a material having a reactive group on the side in contact with the composite film, the reactive group being chemically bonded to the high-molecular weight compound (

Abstract: A method and apparatus for synchronizing the line time and color channel exposure timing signals of a CCD line sensor with the polarization control signal of an AC-polarized arc-discharge lamp in a scanning system. The scanning system comprises a scanner illumination system, including an AC-polarized arc-discharge lamp, for illuminating a document to be scanned, and a scanner imaging system for scanning the illuminated document in a line-wise manner. The scanning system of the present invention is designed to minimize brightness fluctuations on the document being scanned, improving the quality of the scanned image.

Abstract: An amplitude optical modulator which utilizes a two-electrode DFB laser structure. The amplitude optical modulator includes a current generator which can modulate at least one of two currents injected into the DFB laser structure. This modulation displaces a spontaneous emission peak of the DFB laser structure, which leads to an amplitude modulation of the injected optical beam. Such an amplitude optical modulator may find particular application in an optical telecommunications system.

Abstract: An array of reflective LCSLM pixels and control circuits formed on a substrate with a light polarizing layer positioned in overlying relationship to the array. A housing having the array and polarizing layer mounted therein, and defining an opening covered by an optical layer with a reflective member affixed to the optical layer. A light source mounted in the housing so that light is directed onto the reflective member and is reflected uniformly onto the polarizing layer. Electrical connections are made from the array, through leads in the housing and to external contacts. The optical layer including a diffuser forming an image plane for reflected light from the array.

Abstract: A multiple quantum well birefringent spatial light modulator has a substrate, multiple quantum well layers thereon, contacts for applying a biasing electric field across the multiple quantum well layers; and a component for varying the biasing electric field to produce birefringence in the multiple quantum well layer enhanced by the Stark effect and thereby effecting modulation of light exiting therefrom. The electric field may be varied directly by varying the voltage applied across the contacts or by providing a photodetector in series with the multiple quantum well layers and using a writing beam impinging on a photodetector to vary the field.

Abstract: The device of the present invention for an optical rotator and a half-waveplate rotator comprises a retarder or polarization modulator interposed between two crossed or parallel quarter-wave plates, depending on being used as optical rotator or half-waveplate rotator, oriented such that the fast or slow axis of the retarder or modulator is at angle of 45.degree. relative to fast or slow axes of the quarter-wave plates. The rotation angle of the optical rotator and half-waveplate rotator is equal to one-half the retardance of the retarder or modulator and electrically adjustable when using a polarization modulator.

Abstract: Total internal light spatial light modulation apparatus includes a light source for projecting infrared light; a prism for reflecting the projected light from an internal surface therein; and an array of pixel posts made of electrostrictive material and positioned proximate a back face of the internal surface for selectively eliminating pixel areas of reflection of the projected light to form an image thereby. A multiplexer is provided to select a set of pixel posts to be electrically charged which corresponds with the image, and electrical contacts are formed on each pixel post no permit electrical charging of each selected pixel post.

Abstract: An optical color display unit is illuminated and operated with external light (36) consisting of the basic color components. The display unit uses a color-selective matrix (26) of color-selecting elements (28a, 28b, 28c, 42) to separate the incoming external light into its color components (36a, 36b, 36c) according to the refraction and diffraction principles of optics. After separating the light into its color components, the geometry of the color-selecting elements (28a, 28b, 28c, etc.) selectively reflects only one, predetermined color component. The colors of the individual color-selecting elements are chosen such that a color image can be displayed on the screen surface.

Abstract: A liquid-crystal optical switch capable of switching separate optical signals in a physical input channel to a selected output channel. A diffraction grating spatially divides the input channel into its frequency components, which pass through different segments of a liquid-crystal modulator. The liquid-crystal modulator segments are separately controlled to rotate the polarization of the frequency channel passing therethrough or to leave it intact. The channels then pass through a polarization-dispersive element, such as calcite, which spatially separates the beams in the transverse direction according to their polarization. A second diffraction grating recombines the frequency components of the same polarization into multiple output beams.

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: An electro-optic modulator includes a closed loop bias control system for maintaining the modulator at its half-power point by modulating a time varying signal on and off at a modulation frequency f.sub.m. The modulation frequency f.sub.m is much lower than the frequency components within the spectrum of the time varying signal, such that, energy within the time varying signal spectrum is recovered at the modulation frequency when the modulator is not operating at the half-power point. A phase sensitive demodulator operating at the modulation frequency f.sub.m demodulates a signal indicative of the modulator optical output signal to provide a DC voltage signal value indicative of the half-power point bias error value. The time varying voltage signal may be a dither noise signal or any other time varying signal such as a signal with a single frequency component (e.g. a sine or cosine) or a signal with a plurality of frequency components (e.g., a square wave).

Abstract: A family of optical switches employ dielectric film polarizing beam splitters and switchable electro-optic retarder to produce 2.times.2 optical switches which exhibit low crosstalk characteristics while switching unpolarized or linearly polarized collimated light. The switches all contain four port modules through which light enters and leaves the switch. The port modules utilize polarizing beam splitters to separate incoming light into two orthogonal linearly polarized components. The component beams are made parallel after which each passes through an electro-optic retarder. The retarders are electrically driven so as to selectively change the polarization of either one of the two component beams, thus making the polarizations the same. Other polarizing beam splitters are disposed to direct the component beams along one of two pairs of paths as determined by their common polarization.

Abstract: An optical system is disclosed which is for a display apparatus having a light source for emitting read light and a reflection type spatial light modulator for modulating the read light incoming thereto into in accordance with image written thereon. The modulated light is projected onto a screen by a projection lens to display the image. A field lens is provided between the modulator and screen at such a position that both the read and modulated light pass therethrough. The field lens focuses the modulated light on near an entrance pupil of the projection lens so that the intensity of the modulated light is increased.

Abstract: A multiple quantum well optical modulator comprising a multiple quantum well structure embedded in the intrinsic region of an s-i-n+ semiconductor. The s-i-n+ structure causes an electric field to be applied to the multiple quantum well structure which causes uncoupling of the el energy confined level of one layer and the x level of the adjacent layer, thereby changing the absorption of the light and causing modulation thereof.

Abstract: A technique for reducing signal degradation and fading within a long optical transmission by utilizing a rotating waveplate arrangement to rotate the SOP of an optical signal launched into the transmission system, and thereby minimize polarization dependent hole-burning ("PDHB"). This effectively reduces the degree of polarization of the launched optical signal, without degrading the noise and dispersion characteristics of the signal. The rate of waveplate rotation is chosen to ensure that the SOP of the launched signal does not remain at a particular SOP long enough to anisotropically saturate any optical amplifier employed within the transmission system, and give rise to PDHB.

Abstract: A technique for reducing signal degradation and fading within a long optical transmission system by minimizing polarization dependent hole-burning ("PDHB") through the cyclic stressing of a birefringent optical fiber to modulate the SOP of an optical signal launched into the transmission system. This effectively reduces the degree of polarization of the launched optical signal, without degrading the noise and dispersion characteristics of the signal. The modulation frequency of the SOP is chosen to ensure that the launched signal does not remain at a particular SOP long enough to anisotropically saturate any optical amplifier employed within the transmission system, and give rise to PDHB.

Abstract: Optical communication methods and apparatus are disclosed for transmitting two or more optical signals with different optical carrier frequencies on a single optical fiber with high spectral efficiency. Each optical carrier is typically modulated with multiple modulated subcarriers. In one embodiment, an optical phase modulator provides cancellation of second order intermodulation products in each optical signal, thereby permitting the optical carrier frequencies to be spaced by 2f.sub.max, where f.sub.max is the maximum modulation frequency. In another embodiment, a single sideband optical phase modulator provides cancellation of second order intermodulation products and one signal sideband, thereby permitting the optical carrier frequencies to be spaced by f.sub.max.

Abstract: An apparatus receptive of illumination light from an illumination light source for providing a color image on a projection lens includes three displays responsive to a video signal for modulating incident lights to display respective component images, a first dichroic layer for separating the illumination light into a first component light and a first mixed light of different wavelength regions to give the first component light to one of the displays, a second dichroic layer for separating the mixed light into second and third component lights of different wavelength regions to give the second and third component lights to other two of the displays respectively, a third dichroic layer for synthesizing, out of the first, second and third information lights from the displays, the first and second information light, and a fourth dichroic layer for further synthesizing the light synthesized by the third dichroic layer with the third information light.

Abstract: An optical voltage sensor utilizing an electrooptic polymer is disclosed for application to electric power distribution systems. The sensor, which can be manufactured at low cost in accordance with a disclosed method, measures voltages across a greater range than prior art sensors. The electrooptic polymer, which replaces the optical crystal used in prior art sensors, is sandwiched directly between two high voltage electrodes. Voltage is measured by fiber optical means, and no voltage division is required. The sample of electrooptic polymer is fabricated in a special mold and later mounted in a sensor housing. Alternatively, mold and sensor housing may be identical. The sensor housing is made out of a machinable polymeric material and is equipped with two opposing optical windows. The optical windows are mounted in the bottom of machined holes in the wall of the mold. These holes provide for mounting of the polarizing optical components and for mounting of the fiber optic connectors.

Abstract: In a polarization-state converting apparatus for use as an optical isolator, an optical modulator and the like, there are provided a waveguide including a magnetic semiconductor, a device for applying a magnetic field to the waveguide in a first predetermined direction, a device for applying an electric field to the waveguide in a second predetermined direction, and a mode conversion is caused via electrooptic and magnetooptic effects due to the electric and magnetic fields to change the polarization state of light propagating through the waveguide. When used as an optical isolator, the optical isolation is performed to compensate for degradation of the mode conversion rate due to a phase mismatch between light incident upon the waveguide and light emerging from the waveguide.

Abstract: A haze-free light modulating polymer dispersed liquid crystal (PDLC) material is disclosed which comprises a polymer which is birefringent and possesses anisotropic optical properties similar to those of the dispersed liquid crystal such that the PDLC material in its transparent state exhibits a refractive index that is matched for all directions of incident light providing for an optically clear, scatter-free film for all angles of view. Electrooptic light shutters are possible from this material which are transparent in the field OFF-state and opaque in the field ON-state or vice versa, depending upon the liquid crystal phase structure and configuration of the light shutter device.

Abstract: A laser sensor protector is provided comprising a nonlinear dynamic device which has a flat broad band reflectance covering the entire visible range in the on-state and allows for good optical quality and high transmittance (80-90) in the off-state. The device can be constructed using electro-optic materials or nonlinear optical materials. If electro-optical materials, i.e., those for which the refractive index can be controlled by an external field, or nonlinear optical materials, i.e, those for which the refractive index can be controlled by the light intensity, are used to construct the present invention, it is possible to achieve dynamic switching, that is, the device is clear in the off-state and it is highly reflective over a broad band in the on-state.

Abstract: An unassembled simple matrix liquid crystal display (LCD) panel, with strips of highly-conductive material, is tested by extracting a two-dimensional image of the capacitance distribution across the surface of the panel under test (PUT) through illumination of a modulator placed adjacent the surface, such as an NCAP modulator or other liquid dispersed polymer-based device. The light modulator is disposed to allow longitudinal probing geometries such that a measurement of capacitance is developed across a gap between the surface of the panel under test and the opposing face of the modulator which causes a power modulation in the optical energy which can be observed through an area optical sensor (such as a camera) for use in directly produce a two-dimensional spatially-dependent power modulation image directly representative of the spatially corresponding capacitance state on the surface of the panel under test.

Abstract: In an optosemiconductor device including a superlattice configuration (TBQ) of first and second quantum well layers and a potential barrier therebetween, photo-excited carriers are formed in the first quantum well layer and are tunnelled through the potential barrier toward the second quantum well layer, so that the tunneled carriers are accumulated in the second quantum well layer. An electric field is applied to the superlattice configuration to expel the tunneled carriers from the second quantum well layer.

Abstract: A high performance light valve for optimizing the switching of a liquid crystal on an area basis. The light valve uses a transparent charge separation layer to allow for the accumulation of photo-generated charges. The light valve concentrates the light absorption in a narrow charge generation region where high electric fields are present from the junction of dissimilar semiconductor materials. The light valve has a switching characteristic dominated by the light and dark carrier densities in a narrow reversed biased region.

Abstract: An electron wave interference device controlled by a light is disclosed. The electron wave interference device includes a first channel to propagate an electron wave, a second channel arranged with an interval from the first channel for propagating an electron wave, and an magnetic field application device for applying a magnetic field into the first and second channels and a region sandwiched by those channels so as to traverse them. The electron waves which are respectively propagated in the first and second channels mutually interfere, and when the light is irradiated to those channels, a distance between peaks of wave functions of the electron waves which propagate in the channels is changed, so that a phase difference occurs in the electron waves.

Abstract: A contact structure and method of formation of a contact structure for an electro-optic modulator. Linear electrodes on a modulator crystal are covered with a dielectric layer. The electrodes are contacted by way of one or more vias through the dielectric layer. Contact pads are formed over the vias so as to contact the electrode and extend over several adjacent electrodes, providing significantly greater contact area for a driver chip applied to the modulator crystal.

Abstract: An electromagnetic radiation beam scanning system for scanning an object with an electromagnetic radiation beam. The scanning system comprises first and second beam-narrowing devices which are arranged so as to have elongated light-transmission regions, respectively, and which are overlapped each other so that the light-transmission regions intersect each other. Each of the beam-narrowing devices includes a light modulation layer showing an electro-optic effect, first and second electrodes disposed so as to sandwich the light modulation layer, first and second polarizers disposed so as to sandwich the light modulation layer and a power source for applying voltages to the first and second electrodes. The light modulation layer combined with the polarizers forms the elongated light-transmission region in response to application of the voltages to the first and second electrodes due to the power source so as to produce a narrowed beam when a light beam is incident thereon.

Abstract: A scan-exposure apparatus comprises a detector for detecting the values of the digital modulation signal in adjacent time series and the differences of the values therebetween and an exposure time changing device for compensating the time spans of the modulation signal. The detector detects the values of the digital modulation signal in two adjacent units of the time series and the difference between the values. An exposure time compensation device adjusts time spans of the time series of the modulation signal. Thus, the modulation signal pattern is rendered similar to the exposure of the exposure beam.

Abstract: A non-mechanical optical switch is provided for alternately switching a monochromatic or quasi-monochromatic light beam along two optical paths. A polarizer polarizes light into a single, e.g., vertical component which is then rapidly modulated into vertical and horizontal components by a polarization modulator. A polarization beam splitter then reflects one of these components along one path and transmits the other along the second path. In the specific application of gas filter correlation radiometry, one path is directed through a vacuum cell and one path is directed through a gas correlation cell containing a desired gas. Reflecting mirrors cause these two paths to intersect at a second polarization beam splitter which reflects one component and transmits the other to recombine them into a polarization modulated beam which can be detected by an appropriate single sensor.

Abstract: A method of and a device for driving a light shutter having an electrooptical effect to polarize an incident light by applying an electric field to the light shutter. When the light shutter is made activate, an excessive electric field in addition to a half-wave electric field which is a specific one to polarize an incident light at 90.degree. in the static characteristics of the light shutter is applied to the light shutter initially, and subsequently, the half-wave electric field only is applied to the light shutter. To discharge the electric charge accumulated in the light shutter, no voltage is applied to electrodes each of which is provided on the wall of the light shutter so as to oppose each other subsequent to the application of the electric field until the next application thereof.

Abstract: An apparatus and method for measuring an unknown voltage using electro-optic materials includes a beam transmitter, voltage sensor, and a receiver. The beam transmitter generates an electro-magnetic beam directed at an electro-optic material in the sensor. The electro-optic material has a voltage gradient across it due to the unknown voltage. The beam is such that it has components both parallel and perpendicular to the direction of the voltage gradient so that passing through the electro-optic material creates a phase difference between the parallel and perpendicular components. This beam with the phase difference passes to the receiver where the beam passes through a compensator formed by another electro-optic material subjected to a voltage gradient from a measurable voltage. The measurable voltage is controlled to produce another relative phase retardation which compensates for the phase retardation produced at the sensor.

Abstract: A spatial light modulator is disclosed, in which a low dark resistance single-crystal plate is used which is formed of Bi.sub.12 MO.sub.20 (where M is Si, Ge or Ti) or similar type crystal, doped with phosphorus (P) in the range of 0.03.ltoreq.P.ltoreq.0.2 in atomic percentage to provide a dark resistivity far lower than that of an undoped crystal, and a high dark resistance layer, which is of the same crystal structure as that of the single-crystal plate and lattice-matched therewith and has photoconductivity, electro-optic effect and a high dark resistivity, is provided on the light incident side of the single-crystal plate. A tapered low dark resistance single-crystal plate may be used which is formed of Bi.sub.12 MO.sub.20 (where M=Si, Ge, or Ti) or similar sillenite type crystal, doped with phosphorus (P) in the range of 0.03.ltoreq.P.ltoreq.0.

Abstract: An optical element that has a heat control unit comprising an electro-optic material member through which a linearly polarized optical beam penetrates. At least one pair of electrodes is disposed on the electro-optic material member. The electrodes sandwich the optical path of the beam. A voltage is applied to the electrodes to generate an electric field in the electro-optic material member which acts on the beam as a lens when the electric field is generated. The optical element further comprises a unit for controlling a temperature distribution in the electro-optic material member. The temperature controlling unit is disposed on the electro-optic material member.

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: A polarization independent guided wave semiconductor device is realized wherein the waveguide region of the device includes one or more strained quantum well layers wherein strain is designed to be tensile in nature so that energy subbands in the quantum well or wells are displaced by a predetermined amount in a direction opposite to that for the quantum size effect. Polarization independence is achieved when, for a lightwave signal having an incident mean photon energy below the absorption bandedge of the strained quantum well layer or layers, the ratio of the oscillator strengths versus the wavelength detuning for heavy and light holes in a first polarization (TE) is substantially equal to a similar ratio computed in a second polarization (TM). Wavelength detuning is understood to be the difference between the wavelength of operation and the wavelength of an exciton resonance peak. Passive and active or actively controllable waveguides and waveguide devices are described.

Abstract: A spatial light modulating element including an electrooptic and photoconductive single crystal plate, a light-transmitting insulating layer provided on at least one of opposite surfaces of the electrooptic and photoconductive single crystal plate, and a pair of electrodes provided for applying an electric field to the insulating layer and the single crystal plate. The insulating layer is formed from a uniaxial single oxide crystal which is crystallographically oriented such that the insulating layer exhibits neither birefringence, nor an electrooptic effect in a direction of the electric field. The insulating layer may be a LiNbO.sub.3, LiTaO.sub.3 or TiO.sub.2 (rutile) single crystal plate cut normal to the (001)-axis.

Abstract: An electro-optic device, which processes by modulating, switching or gating, a light beam in response to an electrical signal utilizes an electro-optic crystal through which the beam to be processed passes. An electric field is generated by pulses which modulate the crystal's index of refraction and also causes piezoelectric ringing in the crystal. Acoustic energy absorbing material is coupled to the crystal for absorbing the piezoelectrically generated acoustic waves propagating perpendicularly to the applied electric field direction which has been found to be the dominant acoustic mode affecting the birefringence of the crystal and causing the ringing. The field is applied in short pulses (of the order of 10 nsec or less) thereby reducing lower frequencies in the acoustic energy spectrum thereby facilitating the absorption of the ringing energy.

Abstract: A voltage measuring system utilizes an electro-optic voltage transducer (EOVT) in which two beams of polarized light injected into one end of an electro-optic crystal parallel to its fourfold axis of rotary inversion are reflected back through the crystal by a prism so that the optical inputs and outputs, including polarizers, collimators, optic fibers, and fractional wave plates where required, are all located at one end of the crystal, which is preferably connected to the low side of the voltage to be measured. The EOVT is supported substantially only at the end with the optical inputs and outputs, with the free end on which the prism is mounted being substantially unsupported. In one embodiment of the invention, a triangular prism is used to reflect the polarized light back through the prism, in another a pyramid prism is utilized.

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: A device for detecting a charge latent image on a recording medium includes a photo-modulation member having a composite film of high polymer material and a liquid crystal material dispersed in the high polymer material, preferable liquid crystal material having refraction anisotropy higher than 0.18 and droplet size of less than 0.5 micron.

Abstract: An instrument including a light-emitter for emitting a light beam, a sensing head portion through which the light beam is transmitted, a light-detective element receiving the beam from the head portion, and a detector receiving an electric signal from the light-detective element. The head portion has a thermo-optical element for changing a first component of the light beam with an ambient temperature, and an optical element for changing a second component of the beam with an electric quantity. The electric signal produced by the light-detective element has a first and a second component which correspond to the first and second components of the light beam, respectively. The detector determines the ambient temperature based on the first component of the electric signal, and determines the electric quantity based on the second component of the electric signal. The electric quantity may be an AC magnetic field, a current, an AC electric field or a voltage.

Abstract: A photo-driven switching apparatus in which a light beam is switched or modulated by using only light beam(s), comprising (a) a dielectric substrate having "photovoltaic effect"; (b) one or more couples of electrodes formed in or on at least portions of the surface(s) of the substrate so as to polarize the portion(s) positioned between the couple(s) of the electrodes thereby, (c) one or more photo-driving or photo-receiving elements provided at least in the polarized portion(s) of the surface of the dielectric substrate, having a polarization direction arranged at one certain direction, and having photovoltaic effect so as to generate photovoltage; (d) a dielectric rotation element comprising a light beam switching passage or modulator having a couple of polarizers, the polarization direction of each of which is perpendicularly crossed or parallel to each other, positioned on the surface of incoming of a light beam to be modulated, and at the surface of outgoing of the light beam, and a couple of electrodes f

Abstract: An optical information system which uses a liquid crystal television (LCTV) as a one dimensional spatial light modulator (SLM) is presented. An optical carrier wave is generated by polarizing and collimating the output of a laser. The liquid crystal television modulates the optical carrier wave with a digital modulating signal to output thereby a modulated optical signal: An array of photodetectors electroptically connects the modulated optical signal into a modulated electrical signal which is displayed on an oscilloscope. The use of an LCTV as a one dimensional SLM yields higher numerical accuracy and extended dynamic range than two dimensional SLM applications of the same equipment.