Abstract: A method and device for wavelength locking is provided, wherein an element having a wavelength dependent characteristic such as a Fabry Perot etalon is used to provide an output signal having an intensity that varies with wavelength. The intensity of a reference signal derived from an input signal is compared with an output from the Fabry Perot etalon to provide a feedback signal that corresponds to the frequency of the input signal. The system is calibrated before wavelength locking is performed to determine a ratio of intensities that determines a locked state or condition.

Abstract: An improved modulator and methods for making the modulator are disclosed. A membrane, preferably circular in shape, is formed over a region of a substrate in such a way that a gap results between the membrane and substrate forming a modulator cavity. The membrane forms a continuous surface over the cavity. In particular, the membrane is not supported by discrete support arms, but rather extends beyond the modulator cavity. Preferably, holes are formed in the membrane to aid in damping its motion and to allow access to underlying layers during modulator formation. According to the method, the modulator is formed by forming a means for creating a gap between the substrate and the membrane, forming a membrane, forming a lateral conduit to aid in removing the means for creating the gap and, finally, by removing the means for creating the gap.

Abstract: An optical modulator includes a first diffraction grating for separating a light flux of a wide wavelength band into light fluxes of given wavelength bands. The optical modulator further includes an optical modulation element for modulating the separated light fluxes through corresponding picture elements, respectively, and outputting them. The optical modulator further includes a second diffraction grating for synthesizing the modulated light fluxes outputted from the optical modulation element, wherein the first diffraction grating, the optical modulation element and the second diffraction grating are integrally structured.

Abstract: An optically addressed spatial light modulator includes a reflective modulation element, a detector for detecting radiation, a micro-lens focusing a write beam on the detector and a read beam on the modulator element, and a circuit receiving a signal output from the detector generated in response to the write beam. The circuit alters the modulation element in accordance with the signal from the photodetector. The read beam is thus modulated in accordance with the amount of alteration of the modulation element. The read and write beams intercept the micro-lens at different angles and may have the same or differing wavelengths. Including multiple photodetectors on a single pixel allows use of a plurality of write beams. An array of the elements may be used to modulate a plurality of read beams.

Abstract: An improved electro-optic modulator having reduced amplitude of acoustic resonances is provided. Acoustic energy is efficiently removed from the electro-optic crystal and channeled into electrode and side dielectric bars where it is dissipated by materials acoustically matched to the electro-optic crystal, that is, materials that have acoustic impedances within .+-.15% of that of the electro-optic material.

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 passive, picture-resolving detector assembly has a matrix detector (32) and an imaging optical device (16,30) for forming an image of an object scene on the matrix detector. The matrix detector includes a two-dimensional array of detector elements (50) and each of the detector elements (50) is arranged to receive, in cyclic succession, a plurality of picture elements of the image in order to improve resolution. A micro-mechanical mirror array (18) having a two-dimensional array of mirror elements (48) is provided and each of the mirror elements (48) is arranged to be alternatively moved, by control signals applied thereto, into a first operative position or into a second operative position. The imaging optical device comprises a first imaging optical system (16) having a beam axis and arranged to form a high-resolution image of the object scene on the micro-mechanical mirror array (18).

Abstract: An E-O probe with improved spatial resolution has a light transmissive base part, an electro-optic material which is fixed to the base part and has an index of refraction which varies in response to an electrical field from a measured object, and a mirror which is fixed to the electro-optic material and reflects an incident beam penetrating the base part and the electro-optic material. The mirror is formed to be smaller than the incident beam in diameter. The electro-optic material is formed very thin.

Abstract: A multilayer stack of alternating low index and high index of refraction low loss dielectric mirror layers are formed on top of a metallic mirror surface, the thicknesses of the mirror layers being chosen to satisfy the Bragg condition at a selected incident angle of polarized light. The dielectric layer adjacent the metallic reflective mirror substrate can have a thickness which produces circularly polarized light exiting the apparatus. An electro-optical layer of EO material can be substituted for the dielectric layer adjacent the metallic mirror and a controlled elliptically polarized output can be produced by altering the electric field applied across the EO layer. This device can be used as a very high power high speed EO modulator.

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: An array of reflective LCSLM pixels formed on a substrate with a light polarizing layer positioned in overlying relationship to the array. A light source mounted in an optically clear support positioned in overlying relationship to and spaced from the array, so that light evenly illuminates the array through the support and allows passage of reflected light from the array back through the support. Electrical connections are made from the array, through leads in the support and to external contacts. A diffuser mounted in overlying and spaced relationship to the support to form an image plane for reflected light from the array.

Abstract: An optical modulator device comprised of a semiconductor laser acoustically coupled to a thin film resonator is disclosed herein. The thin film resonator includes a piezoelectric crystal layer having first and second opposing surfaces, with the first opposing surface being in contact with a metallic electrode. The semiconductor laser is interposed between an acoustically reflective surface and the second surface of the thin film resonator. In a preferred implementation the acoustically reflective surface is defined by a submount underlying a substrate upon which is mounted the semiconductor laser.A frequency modulator exhibiting an improved modulation index may be achieved by integrating a superlattice structure within the active region of the semiconductor laser.

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: 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: 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: Full complex spatial light modulation is enabled by an optically additive combination of the actions of separate and independent spatial light modulators, even though the independent modulators can each express only a one-parameter subset of complex values called its operating curve. Similarly the operating curve of a single modulator can be shifted (biased) by optically adding a constant complex value.

Abstract: An elegant design for an optical modulator having a high Q is described. The modulator is made up of a straight-forward microwave guide within which a block of a monocrystalline electro-optic material such as lithium niobate is positioned. The modulator is dimensioned to support sequentially standing waves of modulating energy within the desired bandwidth. Optical radiation to be modulated is introduced into the crystal. In one embodiment designed particularly for the 2-15 GHz range, the amount of crystalline material necessary to interact with the incoming radiation is selected to be a minimum, and in another embodiment designed for the 15-75 GHz frequency range, a zig-zag reflection pattern is provided within the crystal.

Abstract: An optically bidirectional electrically controlled optical switch having reduced light loss includes an electro-optic crystal having one set of fast and slow optical axes and having at least two light paths for receiving light beams through the crystal, the crystal exhibiting electric field induced birefringence such that a light beam passing through the crystal along a light path and having a plane of polarization oriented in a first direction may have its plane of polarization switched from the first direction to a plane of polarization oriented in a second direction. Beam splitting polarizers are disposed at each end of the electro-optic crystal and optically aligned with the two light paths. The beam splitting polarizers split the optical beam into two light beams having planes of polarization oriented in the first and second directions when transmitting light to the two light paths and combine the two light beams into a single light beam when receiving light beams from the two light paths.

Abstract: A train of coherent laser output pulses with reduced speckle is generated by providing laser pulses having a first polarization and a coherence length, splitting each pulse in the input laser pulses to provide a first pulse train including a first series of output pulses of the first polarization in output pulses and a second pulse train, and rotating polarization and delaying the second pulse train. The second pulse train is then split to provide a second series of output pulses having a different polarization than the first series of output pulses and a third series of output pulses having a delay length greater than the laser coherence length thereby providing a train of coherent laser output pulses including the first series of output pulses interleaved with the second series of output pulses and the third series of output pulses. The train of coherent laser output pulses can again be split and delayed with polarization rotation to generate a second train of coherent laser output pulses.

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: A device for damping the vibrations of an elongated, substantially rectangular crystal in response to an applied high voltage electrical field comprises a pair of dielectric panes which are impedance matched with the crystal and are attached to opposite sides thereof. As attached to the crystal, each of the panes is disposed at the periphery of the electrical field, and an aluminum block is attached to each of the panes on a surface which is opposite from the crystal. The mass of aluminum blocks, and the texture of their exposed outer surfaces cooperate to mechanically dampen the acoustic vibrations transmitted from the crystal through the panes. Additionally, the rectangular dimensions of the crystal are chosen to delay the propagation of acoustic waves from the surfaces of the crystal to its center.

Abstract: A reflective liquid crystal display includes a retroreflector made of an array of full corner cube elements which have their optic axes tilted away from the normal to the plane of the display by an angle of between about 10.degree. and about 45.degree..

Abstract: An optical space switch includes a polarization controller, a beam splitter, a first reflection block and a second reflection block. The polarization controller has a first mode and a second mode. The polarization controller maintains the polarization of input light in the first mode and changes it by 90.degree. in the second mode. The first reflection block includes a quarter wave plate and a light path changing element. The input light from the polarization beam splitter is reflected by the first reflection block. During this time, the input light passes through the quarter wave plate twice. Thus, the polarization of the input light is changed by 90.degree.. Further, the light path of the input light is shifted by a predetermined distance by the light path changing element. The second reflection block has a quarter wave plate and a mirror. The second reflection block receives the input light from the polarization beam splitter, and returns it thereto.

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: Method and apparatus for electro-optically modulating the intensity of an incident light beam including a coupling prism with a high reflective index, a semiconductor substrate in optical contact with the coupling prism and having a conductive area formed therein, an organic electro-optic film formed on the substrate and covering at least a portion of the conductive area, and a transmission line disposed above the electro-optic film and cooperating with the conductive area to form electrodes for use in applying an electric field across the electro-optic film. Light directed through the substrate by the coupling prism couples with surface plasmons at the film-to-metal interface and is selectively reflected or absorbed depending upon whether or not an electric field is applied.

Abstract: A device for rapidly measuring voltages by electro-optic or magneto-optic ans which exhibits a substantially linear response over much of its operating range. The device employs the Pockels effect in which the orientation of polarized light is altered in direct response to applied voltages. The response of the subject device is made substantially more linear by dividing the polarized light into two beams and retarding the phase of the second beam by one-quarter wavelength, attenuating its intensity by a factor of approximately four, and passing it through a second Pockels cell having a transducer constant of one half that of the first Pockels cell and then recombining, or superpositioning, the first and second beams of light, thus yielding a substantially linear response over much of the applied voltage range.

Abstract: An optical switch for arbitrarily polarized light having low cross-talk is made in which an input beam is split into its TE (s wave) and TM (p wave) polarization components, the TM component is converted to TE by total internal reflection, the two beams are either reflected or transmitted by liquid crystal cells, one of the beams is then converted to TM polarization, again by total internal reflection, and the two beams are recombined and outputted from one of two ports.

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: An efficiency polarization converter of few optical components for converting a randomly polarized light into a single beam of linearly polarized light, comprises a first optical device receiving the random light and projecting two linearly polarized lights one projected in a first direction, another to a second optical device which changes the polarization plane thereof, the polarization changes light being directed by a third optical device to the first direction, thereby the two linearly polarized light are combined and aligned to have a common polarization to become the single beam linearly polarized light projected in the first direction. Typical first optical device is a polarization beam splitter, a typical second optical device is a quarterwave plate with a mirror, a halfwave plate or a Fresnel rhomb with a mirror, or a photomodulation material interposed between biased electrodes with a mirror, a typical third optical device is a polarization beam splitter, a prism or a mirror.

Abstract: A photorefractive system is disclosed containing interposed between electrodes an electrophotographic photoreceptor layer unit and a layer having a second order polarization susceptibility of greater than 10.sup.-9 electrostatic units comprised of organic polar aligned noncentrosymmetric molecular dipoles having an electron donor moiety linked through a conjugated .pi. bonding system to an electron acceptor moiety. The device can be employed to transfer information from one source of electromagnetic radiation to another.

Abstract: There is provided by this invention an electro-optic modulator for damping acoustical energy produced by an electro-optic crystal. The modulator couples acoustic energy from the electro-optic crystal to an acoustic coupler due to the matching acoustic impedances of the coupler and the crystal. The coupler transmits the acoustic wave to the acoustic damper which dampens the acoustic energy. The coupler linearly decreases in height in a direction away from the crystal so that the acoustic wave is reflected through more than one damper prior to returning to the crystal, thus further decreasing acoustical energy. Another feature of this invention is the geometrical design of the electro-optic crystal which has two of its faces, which are not attached to a coupler, positioned not to be perpendicular with a face attached to a coupler.

Abstract: An optical article capable of modulating the reflection of polarized monochromatic electromagnetic radiation is disclosed comprising a reflective metal layer having a thickness of less than 0.5 .mu.m, means acting as a support for directing polarized electromagnetic radiation to the reflective metal layer, a dielectric layer interposed between the support and the reflective metal layer having a refractive index less than that of the support and a thickness in the range of from 0.1 to 10 times the wavelength of electromagnetic radiation directed toward the reflective metal layer, an electrooptic medium that exhibits a refractive index which is a function of an applied electrical potential, and a counter electrode. The optical article is characterized in that it is capable of modulating the reflection of polarized monochromatic electromagnetic radiation from differing wavelength sources to produce a multicolor image.

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.