Abstract: The invention relates to an external cavity tunable laser. The laser comprises an extracavity collimating lens arranged outside a laser cavity, and a laser output mirror, a laser gain medium, an intracavity collimating lens, an active optical phase modulator and a tunable optical filter all arranged sequentially inside the laser cavity. The laser further comprises an active polarization rotator arranged behind the tunable optical filter, a polarization beam splitter arranged behind the active polarization rotator, a first etalon and a first total reflection mirror arranged in the direction vertical to the optic axis of a laser cavity output lens, a second etalon and a second total reflection mirror arranged in the direction of the optic axis of the laser cavity output lens, and a laser drive and control circuit.

Abstract: A tunable laser, including: a laser resonant cavity; a laser gain medium; an intra-cavity collimating lens; an acousto-optic tunable filter; a device exciting sound waves in an acousto-optic crystal; a radio frequency signal source providing radio frequency energy for the energy transducer and adjusting the oscillation wavelength of the laser resonant cavity by changing radio signal frequency; an optical phase modulator disposed between the intra-cavity collimating lens and the acousto-optic crystal; an optical etalon disposed between the optical phase modulator and the laser gain medium; a wavelength locker disposed at one of zero-order diffraction optical paths of intra-cavity light; a pigtailed collimator coupling laser output light to an optical fiber; a pumping source exciting the laser gain medium; a phase modulator driver for driving the optical phase modulator; and a signal control processing circuit.

Abstract: An acousto-optic (AO) device includes an AO interaction crystal for receiving and propagating a light ray along an optical propagation direction (OPD). A piezoelectric transducer is on at least one surface of the AO interaction crystal for receiving an electrical signal and emitting an acoustic wave into the AO interaction crystal. An electrode is on the piezoelectric transducer for coupling the electrical signal to the piezoelectric transducer. The electrode is a patterned electrode that includes a plurality of different transverse edge positions. The plurality of different transverse edge positions span a position range of at least five percent of an average height (Havg) of the electrode.

Abstract: An acousto-optic laser beam scanner of improved scanning angle scope is provided by introducing a controllable compound acoustic waveform into a light transmissive body wherein at least binary and binary diffraction grating patterns of both positive and negative sense can be introduced into the body, the period of the waveform determining the refraction angle magnitude and the order of the pulses determining the refraction angle direction.

Abstract: The subject matter of the invention is a method of high-resolution acousto-optic programmable filtering in the infrared region of an incident optical wave. To that end it proposes the use of a birefringent acousto-optic crystal whereof the propagation speed of acoustic waves is slow, such as compounds of mercury, which acousto-optic crystal comprises, on one of its faces, a piezoelectric transducer designed to generate a transverse acoustic wave with wave vector whereof the energy propagates according to the same axis but in the opposite direction to the energy of the incident optical wave, knowing that the optical wave resulting from the acousto-optic interaction between the incident optical wave and the acoustic wave with wave vector is diffracted perpendicularly or almost perpendicularly to the direction of the incident optical wave.

Abstract: An acousto-optic module is provided, including a number of partially coupled optical resonators distributed within a dielectric medium and at least one acoustic transducer mounted on a surface of the dielectric medium for injecting an acoustic wave into the optical resonators so as to diffract light passing therethrough by means of Bragg diffraction. This acousto-optic module has been applied in particular to an improved tuneable optical filter in which an acoustic shear wave is generated and which travels through the acousto-optic module in a direction substantially parallel with a polarized light signal passing therethrough. The acousto-optic module is also applied to an improved optical frequency shifter.

Abstract: It is an object to perform high-precision observation by compensating group-velocity-delay dispersion and angular dispersion with a simple structure. The invention provides a laser microscope 1 including a light source; an acousto-optic deflector 7 that deflects ultrashort-pulse laser light L emitted from the light source; an angular-dispersion element 8, disposed in front of or after the acousto-optic deflector 7, that applies angular dispersion in a direction opposite to the acousto-optic deflector 7; and a group-velocity-delay dispersion-amount adjusting unit 10 that adjusts the amount of dispersion compensation by moving the angular-dispersion element 8 so as to vary the optical path length at each wavelength between the angular-dispersion element 7 and the acousto-optic deflector 8.

Abstract: An acousto-optic (AO) device for generating a highly apodized acoustic wave field includes a piezoelectric transducer crystal for emitting an acoustic wave having a ground electrode disposed on one side of the piezoelectric crystal, and a patterned electrode layer disposed on a side of the piezoelectric crystal opposite the ground electrode. The patterned electrode layer includes a continuous region proximate to its center and a discontinuous region, a pattern in the discontinuous region including a plurality of spaced apart features electrically connected to the continuous region. An AO interaction crystal which receives the acoustic wave is attached to the ground electrode or the patterned electrode layer.

Abstract: A dynamic beam splitter including a beam deflector having a plurality of operative regions, the beam deflector being operative to receive a laser beam at a first one of the plurality of operative regions, the laser beam passing through the beam deflector, and to selectably direct the laser beam in response to a control input signal to pass through the beam deflector a second time. Methods for splitting a beam and for manufacturing an electrical circuit employing the dynamic beam splitter are also enclosed.

Abstract: A system, method and article of manufacture is disclosed that provides an improved, more efficient, laser beam modulator and splitter. The combined device includes a crystal with a horizontal cross-sectional shape of a pentagon. The crystal includes a top surface, a bottom surface, and a first through fifth sides. The first side and the second side are substantially parallel. An absorber is mounted on the third side. The fourth and fifth sides are substantially opposite to the third side. The fourth and fifth sides form an angle substantially equal to 180 degrees minus the sum of a first a second Bragg angles. The crystal also includes at least one layer. For one embodiment, each layer includes an incident window on the first side, an active window on the second side and a transparent axis between the incident window and the active window. A first and a second transducer are mounted on the fourth and fifth sides.

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: 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: A scanning optical unit is provided which can prevent flare reflection of a laser beam at an end portion of a reflecting mirror which is provided outside an exposure region and which is for detecting a time of starting of exposure by the laser beam. In the scanning optical unit, given that a propagation distance from a transducer of an acousto-optic modulator (AOM) to a diffracted position of the laser beam passing through an acousto-optic modulating medium is L, a propagation speed of ultrasonic waves within the acousto-optic modulating medium is V, a main scanning speed of the laser beam is v, a distance from a position on a reflecting mirror at which the laser beam is reflected onto an SOS sensor to a recording medium side end portion of the reflecting mirror is l, and a focal length of an f&thgr; lens is f, a relationship L<l·V/{v·(f−t)/f} is established so as to prevent flare reflection of the laser beam.

Abstract: An optoacoustic modulator contains first and second optoacoustic media, to which first and second piezoelectric vibrators are attached respectively. Herein, both of the first and second optoacoustic media are designed in same measurements, wherein they are arranged in series along an optical axis of a light signal in such a way that crystal orientation of the first optoacoustic media differs from crystal orientation of the second optoacoustic media with an angle of inclination of 90.degree.. In addition, the first piezoelectric vibrator is attached to a first surface of the first optoacoustic media which is placed in parallel with the optical axis of the light signal, while the second piezoelectric vibrator is attached to a second surface of the second optoacoustic media which is placed in parallel with the optical axis of the light signal, wherein the first surface is directed perpendicular to the second surface.

Abstract: In a non-collinear type acousto-optic tunable filter, the incident angle of a source light beam L.sub.1 radiated from a light source 6 onto an acoustic medium 1 is set at an equivalence incident angle for which the wavelength .lambda..sub.i of the diffracted ordinary ray L.sub.3 and the wavelength .lambda..sub.i ' of the diffracted extraordinary ray L.sub.4 become approximately identical. Further, the diffracted ordinary ray L.sub.3 and the diffracted extraordinary ray L.sub.4 of the approximately identical wavelength are superposed, and the intensity of the superposed ray is detected. Consequently, spectrometry is performed based on the superposed diffracted ray having twice the intensity and a very sharp waveform, so that accurate spectroscopy can be made possible even if the intensity of the source light beam is low.

Abstract: A multichannel acousto-optic modulator (MCAOM) is described which uses a crystal with a plurality of mounting faces for acoustic transducers. The mounting faces are oriented so that the acoustic transducers mounted thereon generate acoustic fields which intersect the incident laser beam at a common angle, i.e., the Bragg angle. A two channel MCAOM uses two transducers. Extension to any higher number of channels follows accordingly. Energizing any of the transducers causes a corresponding first order beam to be diffracted out. Since the acoustic field for each transducer intersects the incident beam with a unique orientation, each first order beam is diffracted out on a unique axis. A system utilizing an MCAOM has electronic means for controlling the driving signals to the transducers to control each channel as required by the application. Amplitude and frequency modulation of the driving signals allows the intensity and angle of the beams to be controlled.

Abstract: An xyz coordinate system is determined so that a z-axis may coincide with an incident direction of an incident light, an x-axis may coincide with a polarizing direction of the incident light and a y-axis may be defined as the right-handed system from the z-axis and x-axis. An acousto-optic element is rotated around the z-axis, around the axis in a direction of propagation of an ultrasonic wave and around an axis B perpendicular to a plane formed by the z-axis and the direction of propagation of the ultrasonic wave, so that the attitude of the acousto-optic element to the incident light is adjusted.

Abstract: An imaging system comprises an acousto-optic tunable filter for receiving light at an input end thereof and outputting light at an output end thereof. A control circuit is provided for tuning the filter. A prism is responsive to the light output by the tunable filter. The prism is oriented at an angle with respect to the filter to compensate for dispersion of the output light caused by the tunable filter.

Abstract: Modulated interference effects arising when laser beams are modulated by photoelastic modulators are substantially eliminated by methods and apparatus that extract from the detected beam the modulated, interfering light that emanates from the optical element of the modulator.

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: A process and a device for compensating wave-front errors occurring in acousto-optical deflectors, with at least one auxiliary deflector which produces a deflected beam whose geometry is independent of the deflection angle and which counteracts the dependence of the deflected beam width on the deflection angle (FIG. 5).

Abstract: An electronically tunable optical filter utilizing noncollinear acousto-optic interaction in an acoustically anisotropic, optically birefringent crystal. The directions of optical and acoustic waves are chosen so that the optical ray is collinear with the group velocity of the acoustic wave. The collinear beam configuration provides increased spectral resolution and reduced drive power.

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.

Abstract: By applying a spatial frequency dependent phase compensation in an optical heterodyning system, a variable rf delay line can be synthesized. The system is able to generate continuously variable phased microwave signals over a prescribed frequency band. A primary application of these variable delay lines is in the area of phased array antenna systems. Because the phototonic delay line synthesizes true time delay, it can be used as part of wide bandwidth system to achieve 100% fractional bandwidth without beam squint. The system lends itself to an optically integrated implementation using a 2-D deformable mirror device to achieve very high packing density which is very useful for an adaptive transversal filter.

Abstract: An acousto-optical deflector disclosed, comprising, two crystals and two piezoelectric transducers associated respectively with the crystals and controlled by a variable frequency RF signal for generating, in the crystals, ultrasonic waves of the same frequency. The crystals are aligned along an acoustic axis for receiving in the aggregate a single incident light beam and generating a single diffracted beam and being spaced apart from each other by a gap creating an acoustic discontinuity without deforming the light beam.