Abstract: In one aspect, frequency fluctuations are stabilized in a laser beam using a frequency stabilization stage that includes a modulator for dithering (i.e., periodically scanning) the frequency of the laser beam, and absorption resonance cell that has a resonance at a predetermined linewidth to which the dithered beam is applied. The output of the cell is synchronously demodulated with respect to the dithering to produce a correction signal that represents the frequency fluctuations with respect to a reference frequency within the absorption linewidth, and the correction signal is used in a configuration which corrects for the frequency fluctuations and produces from the stage a non-dithered, frequency stabilized output. In another aspect, the frequency of the laser beam is controlled using the molecular or atomic resonances of a plurality of successive frequency stabilization stages.

Abstract: A coherent laser radar system in which a number of individual receiver modules are deployed in an area relatively near the targets to receive signals originating at a transmitter located at a much greater distance from the target area. The radar is particularly adapted for the midcource detection and tracking of missiles in space and differentiating between reentry vehicles and decoys. This permits a number of receivers to be positioned at separate points, each capable of receiving and analyzing reflected signals originating from a single transmitter. Direct communication between the transmitter and each receiver permits the transmitter to know at all times the location, velocity and direction of each receiver thus permitting the receivers to be positioned near the targets relative to the position of the transmitter.

Abstract: A pulsed gas laser having two spaced optical resonators each associated with a pair of high voltage electrodes. The first and second pairs of electrodes are positioned within a common plasma chamber including means for circulating a laser gas successively between the two pairs of electrodes. A common heat exchanger removes the heat energy from the two regions of plasma excitation. A high voltage pulse generator connected to the electrodes includes timing means for delaying the application of high voltage pulses to the second pair of electrodes, the delay being either (a) less than the time required for an acoustic shock wave to travel through the lasing gas from the first to the second pair of electrodes or (b) longer than the time required for the shock wave created by the discharge of the first pair of electrodes to die out. Each optical resonator is provided with an adjustable mirror arranged to reflect laser pulses to and from a mirror grating.

Abstract: A system for generating a stable optical frequency from a laser signal having inherent frequency fluctuations. The signal from an injection-controlled pulsed laser is divided into two parts. One part is mixed with the signal from a stable CW laser to generate beat frequencies. These signals are amplified and recombined with the pulsed laser signal in an output modulator. In one embodiment, the difference frequency between the pulsed laser and the reference signal is less than 1000 MHz. The beat frequencies are increased by an X-band mixer to the microwave range where they can be readily amplified in an available broad band amplifier. In another embodiment, the transmitter laser and the reference laser operate at a difference frequency in the microwave range, say, above 5,000 MHz. The beat frequencies are obtained by a high frequency mixer such as a bulk crystal in a waveguide or cavity. In still another embodiment, two independent transmitter lasers generate pulses that occur with a significant time delay.

Abstract: A system for generating a stable optical frequency from a laser signal having inherent frequency fluctuations. The signal from a injection-controlled pulsed laser is divided into two parts. One part is mixed with the signal from a stable CW laser to generate beat frequencies. These signals are amplified and recombined with the pulsed laser signal in an output modulator. In one embodiment, the difference frequency between the pulsed laser and the reference signal is less than 1000 MHz. The beat frequencies are increased by an X-band mixer to the microwave range where they can be readily amplified in an available broad band amplifier. In another embodiment, the transmitter laser and the reference laser operate at a different frequency in the micorwave range, say, above 5,000 MHz. The beat frequencies are obtained by a high frequency mixer such as a bulk crystal in a waveguide or cavity. In still another embodiment, two independent transmitter lasers generate pulses that occur with a significant time delay.

Abstract: A system for generating a stable optical frequency from a laser signal having inherent frequency fluctuations. The signal from an injection-controlled pulsed laser is divided into two parts. One part is mixed with the signal from a stable CW laser to generate beat frequencies. These signals are amplified and recombined with the pulsed laser signal in an output modulator. In one embodiement, the difference frequency between the pulsed laser and the reference signal is less than 1000 MHZ. The beat frequencies are increased by an X-band mixer to the microwave range where they can be readily amplified in an available broad band amplifier. In another embodiment, the transmitter laser and the reference laser operate at a difference frequency in the microwave range, say, above 5,000 MHZ. The beat frequencies are obtained by a high frequency mixer such as a bulk crystal in a waveguide or cavity. In still another embodiment, two independent transmitter lasers generate pulses that occur with a significant time delay.

Abstract: A gas laser is provided in which a replaceable module, comprising a plasma chamber and the associated high voltage components and circuitry, can be quickly and easily replaced by relatively unskilled personnel without any need for optical realignment. Each high voltage electrode of the plasma chamber includes a connector plate that extends through the envelope and engages a support plate of the module containing the high voltage pulse circuitry. These support plates are precisely positioned with respect to two resonator mirrors mounted permanently on a base structure, while the connector plates are precisely positioned with respect to the electrodes and windows of the plasma chamber. The positioning of the connector plates with respect to the electrodes, the windows and the optical axis is identical for each of the replaceable modules.

Abstract: A sensing system for the detection of trace gases in the atmosphere or contaminates on a surface. Particular chemical substances are detected at remote points by placing a sensor unit in the vicinity of the area to be examined and illuminating the area with a laser beam generated by the sensor unit. An optical detector, also carried by the sensor unit, registers the fluorescence produced by the substance illuminated and relays this information by a telemetry link back to the base site. The utility of the system is broadened by providing a chemical reactant selected to react with the substance to be detected to produce a reaction product that fluoresces strongly at the wavelength of the laser light. The chemical reactant is carried by the sensor unit and is sprayed into the area to be examined.

Abstract: Radiation at the frequency of a preselected absorbing resonance is produced by use of split and recombined interfering optical paths, arranged to produce near white light interference effects, and a preselected absorption medium disposed in one path of the interfering configuration. By association of this configuration with a laser oscillator, the regeneration characteristic of the laser oscillation can be determined by a peak in the reflected or transmitted wave produced by the cooperation of the optical interference system and the absorption medium. Use with standing wave, ring, and gain-switched transient lasers all can produce radiation essentially confined to the narrow absorption profile of a selected gas. Improved methods of laser chemistry and remote and close range gas detection are made possible by the new system.

Abstract: A pulsed laser system capable of producing pulses of radiation at relatively high peak power at a single resonator mode, said system comprisinga master laser oscillator capable of producing a beam of radiation at a desired frequency to be introduced to a power laser,a radiation-responsive pulsed power laser oscillator including an optical resonator formed by a set of reflectors, said laser adapted to receive periodic application of a voltage pulse, said optical resonator arranged to receive said introduced beam at least during the periodic application of said voltage pulse to said power laser whereby the frequency of radiation emitted by said power laser can be determined by the frequency of said introduced beam,monitoring means acting between pulses of said power laser to optically monitor the resonator cavity of said power laser to determine the frequency of the resonator mode of said power laser and produce a signal dependent upon said frequency,and stabilizing means responsive to said signal of said monit

Abstract: Stable-frequency optical radiation is generated by use of an electro-optical modulator to produce from radiation of a power laser that has inherent frequency fluctuations, an optical side band of the radiation that has the stable frequency. A modulating signal is applied to the modulator, the signal based upon a difference-frequency signal that represents the difference in frequencies between the output of the power laser and an optical signal obtained from a highly stable reference source. The reference radiation shown is the direct output radiation of a stable reference laser. In one embodiment the pulses of a high power CO.sub.2 TEA laser operating on a single mode are synchronized with a pulsed broad band amplifier which amplifies the difference-frequency signal to produce the modulating signal, and an optical delay in the power laser output path, preceding the modulator, corrects for the delay provided by the amplifier and other sources of delay.

Abstract: Novel laser resonator cavities and laser wavelength tuning arrangements are disclosed. A pair of similar spectral dispersion means achieve in the resonator both a colinear region for rays of different wavelengths and a region in which rays of different wavelengths coextend separated and substantially parallel. Amplifying medium in an optical cavity following at least a first dispersion means, preferably in the parallel region of a laser having paired dispersion means, enable amplification at the different wavelengths while limiting their coupling via the amplifying medium. One or a number of apertures disposed in a dispersed path within a laser cavity are positioned to transmit a selected ray or rays and to block rays of unwanted wavelength whereby laser oscillation wavelength is determined. The above features are variously combined to achieve colinear output beams of various wavelengths and injection-type control of laser oscillation. Variable reflecting optics, e.g.

Abstract: A novel enhanced infrared spectral light source employing gas discharge, to be designated hereafter as EISLS, and a detection system using such an EISLS lamp for gas detection of a given molecular gas, the lamp adapted to produce spectral radiation at selected, sharply defined, spontaneous emission frequencies in the infrared corresponding to an absorbing molecular rotation-vibration transition band of the given gas. According to one feature, a gas mixture within the chamber provides an excitable buffer gas and a quantity of the given gas, the buffer gas having a state excitable by the excitation means and matched to the given gas in the manner that energy from the buffer gas state can transfer via collisions to the given gas and excite the upper levels of the absorbing transition band, whereby resultant radiative decay of the upper levels to the lower levels of the absorbing transition band produces the desired selected spontaneous emissions from the given gas, enhanced by the buffer gas.

Abstract: A memory system is shown in which communication to and from memory cells is effected by optical beams. Memory cells are shown employing elements with negative resistance and operating in either of two stable modes. Other memory cells are shown employing subharmonic oscillators operating in either of two phase relationships. The memory cells and systems permit extremely fast operation.

Abstract: A memory system is shown in which communication to and from memory cells is effected by optical beams. Memory cells are shown employing elements with negative resistance and operating in either of two stable modes. Other memory cells are shown employing subharmonic oscillators operating in either of two phase relationships. The memory cells and systems permit extremely fast operation.

Abstract: Optical radiation generation and detection using metal-to-metal diode junctions. Coherent optical radiation is generated by using an antenna connected to a metal-to-metal diode junction with non-linear current-voltage characteristics and by coupling to the junction electromagnetic radiation energy to interact with the junction, causing emission from the antenna at optical frequency absent from the input. Optical diodes are shown in the forms of a mechanically contacted cat whisker system and as single and multiple microscopic solid portions in an integrated solid mass, defining both the antenna and the junction, preferably as a deposit of solid layers upon a substrate, preferably as overlapping printed circuit line structures. Arrays of such junctions provide enhanced effects; useful arrays include Franklin-Marconi geometries, fish-bone antennas and row and column arrays.

Abstract: Laser detector for gases employs two beams, one at wave length corresponding to an optical absorption resonance of the gas to be detected, 3.39 micron in the preferred methane detector, and another at a similar wave length, but lying outside of the effective absorption curve, with a balance circuit for detection. The embodiments show common beam path, common lasing medium and common power sources for generating the two beams. In one embodiment two resonant cavities share a common discharge tube and output mirror through switching, while in others the resonators are separate but sharing the same gas system or power supply. A suppression cell filled with methane is employed to suppress a dominant transition, to establish lasing at another transition, and adjustable length and adjustable pressure cells are also employed to enable balancing of the system prior to detection.

Abstract: Optical radiation generation and detection using metal-to-metal diode junctions. Coherent optical radiation is generated by using an antenna connected to a metal-to-metal diode junction with non-linear current-voltage characteristics and by coupling to the junction electromagnetic radiation energy to interact with the junction, causing emission from the antenna at optical frequency absent from the input. Optical diodes are shown in the forms of a mechanically contacted cat whisker system and as single and multiple microscopic solid portions in an integrated solid mass, defining both the antenna and the junction, preferably as a deposit of solid layers upon a substrate, preferably as overlapping printed circuit line structures. Arrays of such junctions provide enhanced effects; useful arrays include Franklin-Marconi geometries, fish-bone antennas and row and column arrays.

Abstract: Tunneling electronic devices responsive to infrared and far infrared radiation are formed by overlapping deposits which define ultra-thin dielectric layers (less than aout 10 Angstrom thickness) between metal layers, and contact areas of the order of 1 micron.sup.2 or less. Preferred embodiments feature operation in the negative impedance region, particularly using multibarrier structures or operating at low temperature with both metals superconductors, and incorporation of the same in oscillators and multivibrators. Other embodiments feature two or more such devices in the form of triodes having positive feedback achieved by radiative or inductive coupling using integrally deposited line structures as the respective antennas or inductors. Similar deposited antennas, e.g. dipole antennas, are employed to produce radiative outputs from the devices achieving, e.g. tunable sources of radiation in the far infrared or infrared.

Abstract: Optical radiation generation and detection using metal-to-metal diode junctions. Coherent optical radiation is generated by using an antenna connected to a metal-to-metal diode junction with non-linear current-voltage characteristics and by coupling to the junction electromagnetic radiation energy to interact with the junction, causing emission from the antenna at optical frequency absent from the input. Optical diodes are shown in the forms of a mechanically contacted cat whisker system and as single and multiple microscopic solid portions in an integrated solid mass, defining both the antenna and the junction, preferably as a deposit of solid layers upon a substrate, preferably as overlapping printed circuit line structures. Arrays of such junctions provide enhanced effects; useful arrays include Franklin-Marconi geometries, fish-bone antennas and row and column arrays.