Abstract: Acousto-optical devices utilize crystals of a novel material thallium arsenic sulfide (Tl.sub.3 AsS.sub.3) grown from a melt. A Tl.sub.3 AsS.sub.3 crystal is cut and parallel faces are prepared and polished. A piezoelectric transducer connected to an RF generator is placed on the acoustic face to generate sound waves. The light is directed through the optical face of the crystal and interacts with the acoustic waves. These devices may be used in signal processing, spectrum analyzing, spectroscopic, liquid analyzing and spectral imaging systems.

Abstract: The optical device can examine a spectrum at low resolution and subsequently choose a portion of that spectrum to be examined at higher resolution, using a single detector array for both spectra. The latter spectrum can be chosen to be arbitrarily anywhere within the low resolution spectrum. The device comprises a source of input light, a wedged shaped dispersive device, a first reflective mirror, a second reflective mirror, a RF generator connected to the dispersive device, and a detector array. In operation, the dispersive device provides a low dispersion spectrum in the zero order light when the source of light is impinged upon it. When the RF generator is turned on, a second spectrum which is diffracted is obtained. This will be the high resolution spectrum. By operating near 100% diffraction efficiency, it is possible to switch from one spectrum to the other. By adjusting the RF frequency the band center of the high resolution spectrum can be varied to fall anywhere within the low resolution spectrum.

Abstract: A source of broad-band and/or narrow band optical radiation is detected and identified by apparatus including a pair of acousto-optical tunable filters which diffract from orthogonally polarized components of the optical radiation, a diffracted ordinary polarized beam and diffracted extraordinary beam, respectively. Undiffracted polarized radiation from the two AOTFs is combined and directed to a first detector which may comprise a small array such as a quadrant array. The diffracted ordinary and extraordinary polarized beams are directed to a second detector which is preferably a single large imaging array. A signal processor uses signals from the first detector generated by the undiffracted beams to detect the presence of the source, and polarized spectral signals from the large imaging array to identify the source of the radiation . A control unit generates radio frequency signals which can be rapidly varied in frequency to control wavelength of the polarized beams diffracted by the AOTFs.

Abstract: A remote gas measuring apparatus and method utilizes the optical absorption line characteristics to determine an amount of gas of interest as may exist in an area under study. The remote gas measuring apparatus includes a source of electromagnetic radiation that can be projected toward the area in question and a light collecting arrangement. The light signal received is coupled to a fast light switch modulator which modulates the light signal to a first frequency. A second modulating arrangement modulates the light signal to a second frequency and includes a birefringent etalon device having a periodic spacing equal to the periodicity of the absorption lines of the gas of interest. The second modulating means is further effective such that, when an electric field is applied thereto the transmission spectra associated with the light signal is shifted between spectra which coincide with the absorption lines and spectra which fall between the absorption lines.

Abstract: A gas analyzer arrangement for detecting the presence or quantity of a gas of interest includes a source of electromagnetic radiation for directing a light beam through a light conditioning device such that the light beam is collimated into a parallel beam of light. The conditioned light beam is then directed through a gas sample cell which contains a sample of the gas of interest. The gas of interest has associated therewith, vibrational rotational absorption lines specific to that gas and which are effective for altering the light beam according to the absorption characteristics thereof. The altered light beam is then directed to a birefringent etalon device which has been sized specifically to match those absorption lines of the gas of interest.

Abstract: Disclosed is a crystal 1 of thallium arsenic selenide, thallium arsenic sulfide, thallium vanadium sulfide, thallium phosphorous selenide, lead halide, cadmium sulfide, cadmium selenide, cadmium tin arsenide, cadmium germanium arsenide, indium phosphoride, indium arsenide, or mixtures thereof, doped with a precious metal in an amount of about 25 ppm up to the solubility limit of a precious metal in the crystal. The crystal is useful in nonlinear optical devices, acousto-optical devices, piezoelectric devices, and other types of optical and acoustic devices.

Abstract: An automated acousto-optic tunable filter infrared analyzer system useable in a variety of industrial and commercial control applications. The system relies upon a narrow band pass tunable acousto-optic filter which is selectively tuned by predetermined rf frequency signals to selectively transmit the narrow band pass of interest which corresponds to a specific molecular species for identification and analysis. The system includes a microcomputer and associated memory function to measure and compare detected signals from an infrared detector which converts the filtered infrared signal to an electrical signal. The memory provides control signals for the computer and for controlling the sequence and frequency of rf energy applied to tune the filter. In this way, the near to mid range infrared can be analyzed for absorption bands corresponding to predetermined molecular species such as combustion product gases, and a feedback signal generated to control the combustion process.

Abstract: The compound Tl.sub.3 PSe.sub.4 is disclosed. Non-conducting single crystals of the compound are prepared which have outstanding acousto-optical properties including an exceptionally high acousto-optical figure of merit. The crystals are used in various acousto-optical devices including a display device, a laser modulator, a non-collinear acousto-optical filter, and an acoustic delay line.

Abstract: Single crystals of Tl.sub.3 VS.sub.4 and Tl.sub.3 NbS.sub.4 are disclosed which have useful acousto-optical properties, including low acoustic velocities and high acousto-optical figure of merit. They are used in acousto-optical devices such as a display device, a laser modulator, a non-collinear tunable filter, and an acousto-optical delay line.

Abstract: The compound Tl.sub.3 PSe.sub.4 is disclosed. Non-conducting single crystals of the compound are prepared which have outstanding acousto-optical properties including an exceptionally high acousto-optical figure of merit. The crystals are used in various acousto-optical devices including a display device, a laser modulator, a non-collinear acousto-optic filter, and an acoustic delay line.

Abstract: A method and apparatus for increasing the angular aperture of an acousto-optic device employing an acoustic zone plate positioned on an acoustic input face of an acousto-optic device. The angular spread of acoustic energy within the acousto-optic device is increased over the angular spread obtainable with a single transducer of the same length; thus providing an increased angular aperture for the resultant acousto-optic device.

Abstract: A gas analyzer arrangement for detecting the presence or quantity of a gas of interest includes a source of electromagnetic radiation for directing a light beam through a light conditioning device such that the light beam is collimated into a parallel beam of light. The conditioned light beam is then directed through a gas sample cell which contains a sample of the gas of interest. The gas of interest has associated therewith, vibrational rotational absorption lines specific to that gas and which are effective for altering the light beam according to the absorption characteristics thereof. The altered light beam is then directed to a birefringent etalon device which has been sized specifically to match those absorption lines of the gas of interest.