Abstract: A color changeable pixel comprises a first plate, a second plate and a third plate. The three plates are settled in parallel. The second plate is a deformable and reflective plate. An incident light from one side of the first plate is modulated and only specific frequency light reflects by the second plate. The frequency of the reflected light is related to the distance between the first plate and the second plate. The second plate shifts by the voltage added on the third plate to change the distance between the first plate and the second plate. Therefore, the frequency of the reflected light is altered.

Abstract: This application describes designs, implementations, and techniques for controlling propagation mode or modes of light in a common optical path, which may include one or more waveguides, to sense a sample.

Abstract: An improved system for mounting an optical assembly of a photoelastic modulator (PEM) to permit free vibration of the optical assembly without introducing any stress or strain on the optical element. Moreover, the mounting system, which includes a mounting block (50), elastomeric mount (32), support flanges (36, 38), and a mounting rail (40), facilitates accurate and easy assembly of the optical element into its enclosure (26).

Abstract: This application describes designs, implementations, and techniques for controlling propagation mode or modes of light in a common optical path, which may include one or more waveguides, to sense a sample. As an example, input light in two different optical propagation modes (e.g., the first and second modes) is directed through a common input optical path to the optical probe head which sends a portion of input light in the second mode to the sample. The probe head directs both the light in the first mode and the returned light from the sample in the second mode through a common optical path to a detection module.

Abstract: A diffraction-optical component for providing a radiation-diffracting grating structure is proposed, comprising a surface wave device including a substrate 43, a surface wave source 47 excitable with an adjustable frequency for producing surface waves on a surface 45 of the substrate 43 and an interaction region 17 of the substrate surface 45 which is provided for the radiation to interact with a grating structure provided by the surface waves produced.

Abstract: An electrical variable optical attenuator (10) of the present invention has a housing (1), a cover (2), an attenuating means (3), an optical module (4), an electrical driving element (5), an input fiber (87) and an output fiber (86). The attenuating means includes a carrier (30) having a guide groove (301) and an inner screw (302). A filter (32) is fixed on the carrier. The optical module includes a guide pole (41). The electrical driving element has a screw rod (552), which couples with the inner screw. The attenuating means is assembled inside the optical module with the guide pole being received in the guide groove to confine the direction of movement of the carrier along the screw rod, thus helping to avoid trembling of the filter when the screw rod is rotated.

Abstract: A wavelength converter has a phase modulated periodically modulated structure, where a nonlinear optical coefficient is periodically modulated at a fundamental period &Lgr;0 and the phase of the modulation varies nearly continuously, and the phase variation of the modulation unit structure is repeated at a period &Lgr;ph (>&Lgr;0). A conversion efficiency is made maximum when a phase mismatch amount &Dgr;&bgr; equals 2&pgr;/&Lgr;0±2&pgr;i/&Lgr;ph (i=0, 1, . . . , n, where n is a positive integer), 2&pgr;/&Lgr;0±2&pgr;(2i+1)/&Lgr;ph (i=0, 1, . . . , n), or 2&pgr;/&Lgr;0+2&pgr;i/&Lgr;f (i=m, m+1, . . . .

Abstract: A method and apparatus for accurately and precisely controlling the frequency (wavelength) and periodic frequency modulation of a laser are provided. An ADC (Analog to Digital Converter) is used to sample the output of a modified interferometer used as a delay line discriminator, and quadrature components of the sampled output are generated. An arctangent function (e.g., atan2) is applied to convert the quadrature components to a phase measure that is proportional to the laser frequency. Correlator circuits (e.g., cost-efficient correlator circuits) are provided to extract average frequency, modulation peak deviation, and modulation phase error signals. Control-loop feedback using the extracted signals is used to adjust the average frequency, modulation deviation, and modulation phase to respective set points.

Abstract: The present invention relates to acousto-optic applications of parametric optical apparatuses that use the mechanical energy of elastic oscillations to convert light over a wide range of wavelengths and amplitudes and to generate coherent light.

Abstract: Acousto-optical filter systems for filtering a light beam by generating undiffracted and diffracted light beams within a birefringent crystal and by suppressing the diffracted beam within or at a face of the crystal. Where the two beams are noncollinear, an aperture provides diffracted beam suppression. Where the two beams have different polarization directions, the diffracted beam is suppressed by a polarization analyzer, internal reflection of each beam at a Brewster angle at the surface, total internal reflection of the diffracted beam at the surface, or a suitably oriented multilayer thin film at the surface. Variation of the acoustic frequency provides tunability of the filter.

Abstract: One embodiment of the present invention is an optical delay line that comprises a plurality of optical elements in optical communication with each other, wherein: (a) at least one of the plurality of optical elements is capable of spatially dispersing a spectrum of an optical signal to provide a spatially dispersed optical signal; (b) at least one of the plurality of optical elements is adjustable to affect one or more of a phase delay and a group delay of an optical signal; and (c) at least one of the plurality of optical elements compensates for polarization introduced into the optical signal by others of the optical elements.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: An acousto-optic scanning system, which relies on two counter propagating acoustic waves with the same frequency modulation. This scheme completely suppresses the linear frequency chirp, and thus enables the generation of fast non-linear scans and non-constant linear scans. By changing the phase between the modulating signals, this scheme also provides fast longitudinal scans of the focal point.

Abstract: An optical reticle substrate inspection apparatus is provided with a laser, a first acoustooptical element which scans a laser beam output form the laser, and a second acoustooptical element which generates a virtual image with a concave lens effect to the laser beam output from the first acoustooptical element. The optical reticle substrate inspection apparatus is further provided with a concave lens arranged on the output side of the laser beam of the second acoustooptical element and an optical system which images the virtual image on a reticle substrate being an object to be inspected. The concave lens magnifies the laser beam in a perpendicular direction to the scanning direction by the first acoustooptical element.

Abstract: A scanning microscope is disclosed. The scanning microscope comprises a light source which emits an illuminating light beam for illumination of a specimen, a resonant beam deflection device, for guiding the illuminating light beam over the specimen, which has a resonant frequency and a resonant frequency range, and an independent oscillator with which a drive oscillation, which has a drive frequency within the resonant frequency range can be generated which drives the beam deflection device. Furthermore a method is disclosed for controlling a scanning microscope having a resonant beam deflection.

Abstract: An optical reticle substrate inspection apparatus is provided with a laser, a first acoustooptical element which scans a laser beam output from the laser, and a second acoustooptical element which generates a virtual image with a concave lens effect to the laser beam output from the first acoustooptical element. The optical reticle substrate inspection apparatus is further provided with a concave lens arranged on the output side of the laser beam of the second acoustooptical element and an optical system which images the virtual image on a reticle substrate being an object to be inspected. The concave lens magnifies the laser beam in a perpendicular direction to the scanning direction by the first acoustooptical element.

Abstract: The present invention relates to acousto-optic applications of parametric optical apparatuses that use the mechanical energy of elastic oscillations to convert light over a wide range of wavelengths and amplitudes and to generate coherent light.

Abstract: The present invention has applications that include detecting color variation in a region, for example, color variations due to temperature changes in an area of ocean water, and, in a more specific application, detecting bioluminescence of certain organisms known to attach themselves to various objects. In one aspect of the invention, an acousto-optic tunable filter hyperspectral imaging system is moved across the region to collect a series of images in which each image represents the intensity of light at a different wavelength. In one embodiment, the acousto-optic tunable filter hyperspectral imaging system includes a motion platform for positioning the acousto-optic tunable filter hyperspectral imaging system over successive Y-coordinates of a region in a direction substantially parallel to a direction of motion of the motion platform.

Abstract: An acousto-optic scanning system, which relies on two counter propagating acoustic waves with the same frequency modulation. This scheme completely suppresses the linear frequency chirp, and thus enables the generation of fast non-linear scans and non-constant linear scans. By changing the phase between the modulating signals, this scheme also provides fast longitudinal scans of the focal point.

Abstract: An illuminator has a printed circuit board supporting a ring of light emitting diodes (LEDs). An annular Fresnel lens and the board are both mounted in a housing having a central though-hole for a camera field of view. The lens mixes light from the LEDs in the tangential direction and it also controls spread in the radial direction so there is uniform illumination over a target plane. Any individual point on the target plane receives illumination from over 25% of the light sources. The illuminator is thus particularly effective, compact, and suitable for a wide range of industrial applications. Choice of lens and the spatial arrangement allows versatility. The illuminator design is easily scaleable by changing the size and spacing between the light sources.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A system and method for reducing or eliminating the speckle intensity distribution of a laser imaging system. In one embodiment of the invention, a radio frequency signal is injected into a semiconductor laser light source (12) for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, optical feedback is used to induce a laser light source for a projection system (10) to create different speckle patterns that blend together on a projection surface (19). In another embodiment of the invention, the laser light source wavelength is Doppler shifted to produce different speckle patterns. In another embodiment of the invention, a means of deflection is used to directionally move the beam to reduce noticeable speckle.

Abstract: A method for increasing the tunable range of a single acousto-optic tunable filter includes the steps of generating an active steering beam on a piezoelectric transducer and configuring the electrodes of the piezoelectric transducer to reduce the tuning frequency at short wavelengths and increasing the tuning frequency at long wavelengths. The piezoelectric transducer is mounted in relation with an optically transparent crystal at an angle such that the fixed launch angle in combination with the driving frequency provides a greater that one octave spectra to be filtered in a single AOTF.

Abstract: An acousto-optic tunable filter (AOTF) utilizing phased array transducers for use as dynamically reconfigurable wavelength division multiplexer. The new type of AOTF has the unique capability of simultaneous and independent selection of multi-wavelength signals and separation into multiple output ports. Preferred embodiments of the AOTF are described that provide increased resolution, narrow channel spacing, lower drive power and reduced coherent crosswalk.

Abstract: An optical reticle substrate inspection apparatus is provided with a laser, a first acoustooptical element which scans a laser beam output form the laser, and a second acoustooptical element which generates a virtual image with a concave lens effect to the laser beam output from the first acoustooptical element. The optical reticle substrate inspection apparatus is further provided with a concave lens arranged on the output side of the laser beam of the second acoustooptical element and an optical system which images the virtual image on a reticle substrate being an object to be inspected. The concave lens magnifies the laser beam in a perpendicular direction to the scanning direction by the first acoustooptical element.

Abstract: An apparatus for performing high speed scanning of an optical delay and its application for performing optical interferometry, ranging, and imaging, including cross sectional imaging using optical coherence tomography, is disclosed. The apparatus achieves optical delay scanning by using diffractive optical elements in conjunction with imaging optics. In one embodiment a diffraction grating disperses an optical beam into different spectral frequency or wavelength components which are collimated by a lens. A mirror is placed one focal length away from the lens and the alteration of the grating groove density, the grating input angle, the grating output angle, and/or the mirror tilt produce a change in optical group and phase delay. This apparatus permits the optical group and phase delay to be scanned by scanning the angle of the mirror. In other embodiments, this device permits optical delay scanning without the use of moving parts.

Abstract: The method and apparatus for amplitude modulation of unpolarized light by at least one Bragg modulator on the basis of domain-invertible material, the unpolarized light is modulated by a first Bragg modulator both for defining a polarization plane in the unpolarized light and for modulating a light part to be allocated to the polarization plane. A second Bragg modulator is provided which modulates the light part of the unpolarized light allocated to the polarization plane orthogonal to the polarization plane of the first Bragg modulator. The method and apparatus are particularly useful for recording a product to be printed, such as for manufacturing printing forms.

Abstract: A projector for producing a visually perceptible light image along predetermined vector coordinates, includes a light source for producing a beam of light along a light path; a deflector positioned to deflect the beam of light along the vector coordinates; a focusing lens for focusing the deflected light beam; and a projection reflector for reflecting the beam along the vector coordinates to thereby form the visually perceptible light image. A preferred light source comprises a laser, and a preferred reflecting surface has a substantially convex shape, preferably including a parabolic reflector.

Abstract: An optical modulation scheme for transmitting data over a fiber optic transmission line is proposed where the following steps are realized:

Abstract: The invention describes a highly compact laser scanning microscope with integrated short-pulse laser. Direct coupling or a fiber coupling of the short-pulse laser with the laser scanning microscope is advantageously circumvented with this arrangement. This compact arrangement of the laser in the scan module of the laser scanning microscope can be used in a particularly advantageous manner, for example, in multiphoton microscopy for three-dimensionally resolved microscopic analysis, e.g., of biological specimens. Because of the inherent depth discrimination of the multiphoton technique, confocal pinholes can be entirely omitted in the detection beam path. Accordingly, the microscope system can be realized in a very simple manner with respect to engineering and is particularly simple to handle with respect to application.

Abstract: An apparatus for performing high speed scanning of an optical delay and its application for performing optical interferometry, ranging, and imaging, including cross sectional imaging using optical coherence tomography, is disclosed. The apparatus achieves optical delay scanning by using diffractive optical elements in conjunction with imaging optics. In one embodiment a diffraction grating disperses an optical beam into different spectral frequency or wavelength components which are collimated by a lens. A mirror is placed one focal length away from the lens and the alteration of the grating groove density, the grating input angle, the grating output angle, and/or the mirror tilt produce a change in optical group and phase delay. This apparatus permits the optical group and phase delay to be scanned by scanning the angle of the mirror. In other embodiments, this device permits optical delay scanning without the use of moving parts.

Abstract: An acousto-optic modulator including an ultrasonic medium for controlling light from an optical source through diffraction, two transducers each having one electrode formed on one side thereof, the electrodes being for generating an acousto-elastic wave, and a conductive adhesive layer interposed between the ultrasonic medium and each of the sides of the transducers opposite to the sides on which the electrodes are installed, in order to adhere each of the transducers to the ultrasonic medium.

Abstract: An apparatus for performing high speed scanning of an optical delay and its application for performing optical interferometry, ranging, and imaging, including cross sectional imaging using optical coherence tomography, is disclosed. The apparatus achieves optical delay scanning by using diffractive optical elements in conjunction with imaging optics. In one embodiment a diffraction grating disperses an optical beam into different spectral frequency or wavelength components which are collimated by a lens. A mirror is placed one focal length away from the lens and the alteration of the grating groove density, the grating input angle, the grating output angle, and/or the mirror tilt produce a change in optical group and phase delay. This apparatus permits the optical group and phase delay to be scanned by scanning the angle of the mirror. In other embodiments, this device permits optical delay scanning without the use of moving parts.

Abstract: A transflective color display having apertures in reflective electrodes through which light from a backlight (9) passes in the transmissive mode. The switching behavior for both the reflective and the transmissive mode is made identical by introducing a retardation plate (11). The transmission efficiency is further increased by using only a monochrome green mode in transmission.

Abstract: The invention features systems and methods for generating optical beams having substantially orthogonal polarizations for use in distance measuring interferometry. In one embodiment, the invention features a system including a source which during operation generates two nonparallel propagating source beams; and a retarder element positioned to receive the two nonparallel propagating source beams and convert them into two nonparallel propagating output beams that are polarized substantially orthogonal to one another. The system can further include a birefringent prism positioned to receive the two nonparallel propagating output beams and produce two parallel output beams.

Abstract: A variable acousto-optic spectrum projector is disclosed. The invention may include a radiation source, an entrance slit, a lens or mirror, a Bragg cell, an arbitrary function generator for driving a transducer of the Bragg cell, another lens or mirror, an exit slit, and a collimating lens. In a first embodiment of the invention, the Bragg cell comprises a Tl3AsSe3 crystal and emits light in the 7 to 11 &mgr;m range (long-wave infrared) with a spectral resolution of between 4.5 and 7 cm−1. In a second embodiment of the invention, the Bragg cell comprises a TeO2 crystal and emits light in the 420 to 720 nm range (visible) with a spectral resolution of between 50 and 80 cm−1.

Abstract: A laser beam intensity modulation system has a variable delay circuit that is used to control the relative delay in the delivery of a video signal between two cascaded AOM's. This delay circuit is controlled by a delay controller that monitors the intensity modulation of the laser beam to provide feedback control. This system maximizes the rise and fall times of the beam to generate precise beam modulation required for high speed image setters.

Abstract: A method and apparatus for overcoming polarization induced signal fading in both heterodyne communication and interferometric sensing. An adjustable birefringent element in series with a linear-polarization beam splitter forms an elliptical-polarization beam splitter. The birefringent element controllably evolves the states of polarization of two input signals thereby controlling the power contribution of each signal onto the orthogonal axes used by the linear beam splitter. When the states of polarization are evolved such that there are equal signal to reference power ratios on the beam splitter axes, subsequent detectors generate a constant, optimum amplitude signal without the need for weighting or decision circuits.

Abstract: An acousto-optic tunable filter based on isotropic acousto-optic diffraction using phased array transducers. The isotropic AOTF provides the advantages of narrow optical passband, low acoustic frequencies, and insensitivity to the input optical polarization. Preferred embodiments of the isotropic AOTFs are described for optimized spectral resolution and diffraction efficiency.

Abstract: Disclosed is a high-speed frequency modulation signal source which has a voltage-controlled oscillator to which a voltage is input to change an oscillation frequency; and a frequency down converter in which a frequency output from the voltage-controlled oscillator is converted into a desired frequency. Also disclosed is a high-speed variable optical wavelength filter which has the above high-speed frequency modulation signal source; a band-pass filter in which a frequency component is extracted from the desired frequency output from the high-speed frequency modulation signal source; and an acousto-optic filter which is driven by the frequency component output from the band-pass filter.

Abstract: An optical scanning device having a scanning speed which can be used in a laser beam printer, a digital copier, a facsimile apparatus or the like, an optical scanning method using the optical scanning device, and an image forming apparatus using the optical scanning device are disclosed. The optical scanning device comprising: a light source for emitting a laser beam having a constant divergent angle; a thin film waveguide; means for coupling the laser beam to said thin film waveguide; and a comb-like electrode for exciting a surface acoustic wave of a high frequency sweep signal so that the laser beam is deflected to be output as parallel rays.

Abstract: A phase modulator is provided with supports attached to the resonating element. The supports have a length which is an odd number of quarter wavelengths of a longitudinal acoustic wave excited in the supports by the resonating element. As such, a longitudinal acoustic wave excited at the resonating element end of the support travels along the support, is reflected at the other end of the support, and returns in opposite phase to that of the excited wave, thereby causing a null in longitudinal amplitude of the wave and reducing the damping of the resonating element.

Abstract: Optical systems are disclosed which are capable of generating and rapidly changing time delays of electrical signals for true time delay beam formation and beam steering and for signal processing applications. The systems utilize an interferometer configuration. A first optical modulator in a first leg of the interferometer is used to modulate coherent light with the signal to be delayed. In a second leg of the interferometer, a second optical modulator provides beam steering to a prism stack, which produces a set of plane reference waves having a range of orientations required to generate a desired range of time delays. Preferably the optical modulators are acousto optic Bragg cells. Alternatively, a stack of lens pairs or diffractive optical elements or a holographic optic element may be used in place of the prism stack. The modulated optical signal from the first leg interferes on an array of photodiodes with the reference waves from the second leg.

Abstract: A signal filter, and method of signal filtering, in which an optical signal s spatially dispersed according to frequency, and undesired frequencies blocked out. In an embodiment, a Bragg cell receives a (typically microwave) signal, and transduces it to an acoustic signal. A light source, e.g. a laser diode, directs light through the acoustic signal in a known manner so as to produce an optical output which is spatially dispersed according to frequency. A programmable spatial light modulator blocks out unwanted frequency components. Upon removal of the optical carrier, e.g. by heterodyning the spatial light modulator's output with a reference signal from the light source, the components can be recombined into a resultant filtered signal. The invention can be used as a repeater, a military electronic countermeasure, in environments which have large amounts of electromagnetic clutter but in which one does not want the clutter repeated.

Abstract: Low-cost, thin-layer liquid crystal (LC) millimeter wave (MMW) phase modulators and phased array antennae are provided based on several types of open transmission strip-line, parallel-line, and ridge-guide configurations in which surface-aligned LCs are modulated reversibly with small applied electrical fields. Incorporated properly in the open transmission lines, the LC layer can modulate the propagating MMW with nearly its full value of birefringence. The modulator comprises: (a) at least one transmission line supported on a first substrate; (b) a dielectric medium comprising a liquid crystal or a liquid crystal composite and contacting the substrate and the transmission line(s), the liquid crystal or a liquid crystal composite (e.g.

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: Deleterious feedback reflections from a power amplifier into a laser master oscillator are eliminated by interposing a nonreciprocal frequency shifter between the oscillator and amplifier, which shifts the laser frequency by more than twice the bandwidth of the laser oscillator resonant cavity.

Abstract: Optical systems are disclosed which are capable of generating and rapidly changing time delays of electrical signals for true time delay beam formation and beam steering and for signal processing applications. The systems utilize an interferometer configuration. A first optical modulator in a first leg of the interferometer is used to modulate coherent light with the signal to be delayed. In a second leg of the interferometer, a second optical modulator provides beam steering to a prism stack, which produces a set of plane reference waves having a range of orientations required to generate a desired range of time delays. Preferably the optical modulators are acousto optic Bragg cells. Alternatively, a stack of lens pairs or diffractive optical elements or a holographic optic element may be used in place of the prism stack. The modulated optical signal from the first leg interferes on an array of photodiodes with the reference waves from the second leg.

Abstract: Devices for deflecting an optical beam under the action of an ultrasonic beam propagating in a block of active acousto-optical material and operating under Bragg tangential conditions, with the acousto-optical interaction being anisotropic. The devices also include entry and exit faces into this material blocks which are inclined at angles .alpha. and .beta. such that the incoming beam and the emerging beam after the interaction are significantly parallel, keeping operation under Bragg tangential conditions. The devices can also be used to make a spectrum analyzer with a very large number of points and very high dynamics.

Abstract: An acousto-optic apparatus is described that varies the time delay of electrical signals over a continuum of delays. In the preferred embodiment, a light source, which can be either coherent or incoherent, emits an optical beam that is focused into an acousto-optic cell. An input electrical signal is used to drive the acousto-optic cell which, in turn, modulates the focused optical beam. Portions of the input optical beam are modulated and diffracted at angles proportional to the frequencies and phases contained in the input electrical signal. By appropriately choosing the cone of angles at which the light is focused into the acousto-optic cell, the diffracted optical beam can be made to overlap with portions of the undiffracted, unmodulated optical beam. All of the light exiting the acousto-optic cell is then collected onto a device for detection. Optical photomixing of the diffracted beam and the undiffracted beam is performed in order to derive the input electrical signal with a time delay.