United Technologies Corporation

US Government As Represented by the Secretary of the Army

Robert J Wayne

Peter P Chenausky

Robert J Mongeon

Lanny M Laughman

Carl J Buczek

Robert W Henschke

Richard A Hart

Ronald E Belek

The apparatus is part of an optical radar set and comprises a high powered O.sub.2 pulsed transmitter laser which is injection controlled to operate at a fixed frequency offset from a lower powered CO.sub.2 local oscillator laser. A portion of the output of the local oscillator laser is applied to an acousto-optic Bragg cell, together with an RF signal equal to the desired intermediate frequency of the radar set. The upshifted first order output of the Bragg cell is injected into the transmitter laser for stabilization purposes. This results in a stable intermediate frequency for the optical radar set.

Optical radar transceiver control apparatus

This multi-format modulated laser may be programmed to produce a variety of utput waveforms by applying a different one of a plurality of modulating waveforms thereto. The outputs can include continuous waves, both modulated and unmodulated, Q-switched pulses, cavity dumped pulses, shaped pulses and mode locked pulses. The laser is provided with an intracavity electro-optic modulator and may comprise two coupled cavities with a gain cell in one cavity and the modulator in the other cavity.

Programmable multifunction laser

The intracavity modulated laser includes a main cavity and an adjacent coed cavity with a gain cell in the main cavity and an electro-optic modulator in the coupled cavity, the cavities being coupled in such a way that the energy level in the coupled cavity during laser operation is much lower than that in the main cavity, and whereby the modulator can selectively affect the polarization of energy in accordance with a voltage applied thereto to selectively couple energy out of both cavities in a desired manner.

Modulated infrared laser with two coupled cavities

An RF discharge waveguide laser is modulated by an electro-optic modulator positioned in a second optical cavity coupled to a gain cavity containing the waveguide.

Coupled waveguide freespace laser

An electro-optically Q-switched cavity-dumped laser is improved by the addition of an injection control laser, so that time jitter is reduced, frequency stability is improved, higher peak circulating power in the Q-switch pulse is achieved, an intracavity grating is no longer required.

Injection control of an electro-optically Q-switched cavity-dumped laser

An improved electrode configuration and method for the deposition of electrical power into an electric discharge laser having a gas path transversely disposed to an optical axis and the electric field is disclosed. The electrode configuration includes a cathode, having one or more common geometry rod elements of a thoriated material disposed transverse to a gas path and a planar anode disposed opposite the cathode in a parallel relationship thereto wherein the cathode and the anode define the gas path therebetween. The electrode configuration is adapted for operation without ballast resistance in the electrical circuit and without the utilization of preionization means. The electrode configuration provides a discharge having substantially diffuse and uniform characteristics within the discharge region.

Apparatus and method for deposition of electrical power in an electric

An improved electro-optic moduator device is disclosed which provides strain-free mounting of an electro-optic crystal within a housing assembly and suppression of acousto-optic effects within the crystal. An acoustic matching liquid having an acoustic impedance substantially matching the acoustic impedance of the electro-optic crystal is disposed within the housing enveloping longitudinally the crystal. The acoustic matching liquid effectively suppresses the acousto-optic resonances within the crystal by coupling the acoustic energy out of the crystal into the liquid. The liquid enveloping the crystal also provides a uniform heat conduction path for minimizing thermal gradient variations and the resulting thermally induced strain within the crystal. A zinc oxide suspension in silicone oil is an exemplary acoustic matching liquid for gallium arsenide or cadmium telluride crystals. In one embodiment the acoustic matching liquid has a consistency of a slurry capable of being recirculated through the housing to improve the heat transfer characteristics of the liquid. In a further embodiment an acoustic absorber, disposed in a spaced apart relationship about the crystal, is adapted for absorbing acoustic energy transmitted through the liquid. An elastomeric seal at each end of the crystal provides a liquid-tight seal between the housing and the crystal to maintain the liquid within the housing and provides a soft-mounting structure to minimize thermally and mechanically induced strain within the crystal.

Electro-optic modulator with improved acousto-optic suppression, heat

A method for cavity dumping a Q-switched laser having a gaseous gain medium to obtain submicrosecond output pulses, typically controllably variable between ten and three hundred nanoseconds at a high pulse repetition frequency typically up to at least twenty-five thousand pulses per second is disclosed. In a laser adapted for continuous wave operation, a combination of a retardation element and an electrooptic modulator provides a first polarization state to intracavity radiation incident onto an intracavity polarization coupler oriented to couple out of the cavity radiation having the first polarization state to provide a high loss condition to the cavity to maintain the laser below threshold. A voltage applied quickly to the modulator converts the first polarization state to a second polarization state to provide a low loss condition to the cavity to Q-switch the laser. Terminating the voltage near the maximum Q-switch buildup converts the polarization to the first polarization state which is cavity dumped by the polarization coupler to provide an output pulse. Controlling the fall time of the voltage termination controls the pulse width of the output pulse while controlling the duration of the voltage controls the energy of the output pulse.

Method for cavity dumping a Q-switched laser

A laser having a gaseous gain medium capable of continuous wave operation and including an etalon with a Stark active gas disposed therein, adapted for providing submicrosecond pulses is disclosed. A method of utilizing the Stark effect to tune rapidly an etalon to form an output mirror having a variable reflectivity to Q-switch and cavity dump the optical flux within a laser to provide an output pulse of laser radiation having a submicrosecond pulse width, typically variable between fifty and three hundred fifty nanoseconds, at a pulse repetition frequency up to twenty-five kilohertz is disclosed. A laser typically having a carbon dioxide gain medium adapted for continuous wave operation includes a grating defining one end of the laser resonator and an output mirror defining the other end wherein the output mirror is an etalon formed with two mirrors containing a switching cell having a Stark active gas disposed therein. A voltage applied to the switching cell rapidly transforms the highly transmissive state of the output mirror to a highly reflective state to Q-switch the laser. Terminating the voltage rapidly transforms the highly reflective state of the output mirror to its original highly transmissive state to cavity dump the Q-switched optical pulse. Controlling the width, fall time and repetition rate of the voltage pulse controls the pulse intensity, pulse width and pulse repetition frequency of the laser output pulses.

Growing community of inventors

Glastonbury, CT, United States of America

Robert J Wayne