Abstract: An array of discrete catalyst elements is contained in a heated module external to the main laser vessel with an auxiliary gas flow loop connecting them so as to provide independent control of catalyst temperature and gas flow rate to achieve high CO+1/2O2 to CO2 recombination under high pulse repetition frequency operation for a sealed laser. Catalyst elements in the form of cylinders with holes through their centers are mounted on multiple parallel rods or catalysts in the form of small spherical or cylindrical elements are contained in multiple packets arranged in the module so as to minimize flow impedance and maximize laser gas recycling throughput. The cylindrical catalyst module is constructed so as to allow for rapid heating to operating temperature while withstanding atmospheric differential pressures during laser processing.

Abstract: Multiple independent electrode sets of a CO2 gas laser are arranged in series within a single optical resonator with each electrode set energized by an independent power source. The total length of the electrode sets together and their maximum power are optimized for output energy at the weakest laser wavelength, and one or several of the independent electrode sets is turned off and/or their power reduced to achieve laser output on strong lines without damage to the laser optics. The total resonator length is chosen to produce an output laser beam with single transverse mode.

Abstract: A CO2 gas flow laser with multiple discharge modules places acoustic baffles between the discharge modules to suppress shock waves and ions passing between the discharge modules such as may disrupt the optical path of the laser. A catalyst may be placed in a center of a toroidal recirculation chamber of the laser and may have integrated filters to prevent catalyst particulates from coating the chamber optical windows.

Abstract: An array of discrete catalyst elements is contained in a heated module external to the main laser vessel with an auxiliary gas flow loop connecting them so as to provide independent control of catalyst temperature and gas flow rate to achieve high CO+1/2O2 to CO2 recombination under high pulse repetition frequency operation for a sealed laser. Catalyst elements in the form of cylinders with holes through their centers are mounted on multiple parallel rods or catalysts in the form of small spherical or cylindrical elements are contained in multiple packets arranged in the module so as to minimize flow impedance and maximize laser gas recycling throughput. The cylindrical catalyst module is constructed so as to allow for rapid heating to operating temperature while withstanding atmospheric differential pressures during laser processing.

Abstract: A CO2 gas flow laser with multiple discharge modules places acoustic baffles between the discharge modules to suppress shock waves and ions passing between the discharge modules such as may disrupt the optical path of the laser. A catalyst may be placed in a center of a toroidal recirculation chamber of the laser and may have integrated filters to prevent catalyst particulates from coating the chamber optical windows.

Abstract: A wavelength conversion system and method. The inventive system is adapted to receive a beam of input energy having a first spiked portion with a first wavelength and a first spatial and/or temporal intensity profile and a second tail portion with the first wavelength and a second spatial and/or temporal intensity profile. The inventive system includes an electro-optic switch (14) and first polarizer (16) for directing the first portion of the input beam along a first processing path (18) and a second portion thereof along a second processing path (20). A first SHG/OPO arrangement (22, 24) is disposed in the first path (18) for shifting the wavelength of the first portion of the input energy from the first wavelength to a second wavelength. The first arrangement is optimized for the first spatial and/or temporal intensity profile of the first portion of the energy.

Abstract: A chemical sensor comprising a gas detector having first and second printed wiring boards with opposed separated pairs of signal and grounded counter electrodes and processing electronics for processing ionic current signals derived from the signal and counter electrodes. A corona discharge source is provided that produces an ionized air stream containing a chemical that is to be detected. An insulating plate is disposed between the second printed wiring board of the gas detector and the corona discharge source that is used to electrically isolate the electrodes and processing electronics of the gas detector from the corona discharge source. An air flow passage is formed through the corona discharge source, the insulating plate, and the gas detector that allows the ionized air stream generated by the corona discharge source to flow past the signal and counter electrodes, so that the chemical may be detected.

Abstract: A corona discharge pollutant destruction system has two or more corona discharge reactors in series, with each stage optimized for either oxidation of hydrocarbons (HC) and carbon monoxide (CO) or reduction of nitrogen oxides (NO.sub.x). The reactors may be arranged with initial oxidation stages followed by reduction stages. Alternatively, the oxidation and reduction reactors may be arranged in alternate stages, with each oxidation reactor followed by a reduction reactor. The treatment of different pollutants by different reactors is achieved by supplying the different reactors with different power levels.

Abstract: A corona discharge pollutant destruction system has two or more corona discharge reactors in series, with each stage optimized for either oxidation of hydrocarbons (HC) and carbon monoxide (CO) or reduction of nitrogen oxides (NO.sub.x). The reactors may be arranged with initial oxidation stages followed by reduction stages. Alternatively, the oxidation and reduction reactors may be arranged in alternate stages, with each oxidation reactor followed by a reduction reactor. The treatment of different pollutants by different reactors is achieved by supplying the different reactors with different power levels.

Abstract: A remote laser sensor incorporating a single integrated detector. The laser sensor comprises a laser for transmitting laser energy that is applied to a target, and a beamsplitter for sampling of the transmitted laser energy. A telescope is provided for collecting laser energy reflected from the target. The integrated detector comprises an integrating sphere for receiving the sampled transmitted laser energy and for receiving the laser energy reflected from the target, and a detector coupled to the integrating sphere for selectively detecting the sampled transmitted laser energy and the laser energy reflected from the target. A scatter plate may be disposed inside the integrating sphere for preventing photons from entering the detector that result directly from a first scattering event within the sphere. In operation, the laser provides a transmit beam that is directed at the target and reflected energy from the target is collected by the telescope and focused onto the detector.

Abstract: Low power discharge preionizers, or species, are provided by a ionizable species generator that preconditions a laser gas to eliminate arcing in lasers, such as pulsed (high repetition rate) lasers. The present invention creates the species in a low power discharge and the species prevents initial arcs from occurring between high voltage electrodes of the laser. The laser comprises a pressure vessel containing the laser gas, a fan for circulating the laser gas, a heat exchanger, a catalyst, and two high voltage discharge electrodes for exciting the laser gas to create lasing. A high voltage power source is coupled to the electrodes for providing a discharge voltage thereto. A primary auxiliary discharge source is disposed adjacent to the electrodes that is used as a preionizer that creates a low density of charged particles in the main discharge volume to act as a uniform seed for the main voltage pulse derived from the electrodes.

Abstract: A laser protection device employing a gas plasma switch wherein applied laser radiation is focused inside a gas chamber, and a nuclear source is employed to pre-ionize the gas volume, whereupon focused laser radiation causes gas breakdown and plasma formation that attenuates the radiation. Specifically, the invention reduces the threshold of plasma switch initiation by incorporating a nuclear source within the gas chamber that constantly injects plasma forming seed particles into the vicinity of a focused laser beam. The plasma resulting from avalanche ionization of the seed particles reflects, absorbs and deflects the laser radiation. The nuclear source introduces charged particles, excimers and metastable atoms with low ionization potential into the gas chamber. Such charged particles are effective plasma initiators because they have low ionization thresholds. The present invention has been found well suited to protect against pulsed laser sources because of fast rise times and high attenuation levels.

Abstract: A catalyst for reacting carbon monoxide and oxygen to form carbon dioxide, comprising platinum black deposited on a platinum wire, and having a moderate activation temperature of about 150.degree.-300.degree. C. A catalytic apparatus includes this catalyst, means for directly heating the catalyst, and electronic means for controlling and monitoring the heating of the catalyst. Carbon dioxide laser systems incorporating this catalytic apparatus are also disclosed.

Abstract: The invention is a laser power limiter. The limiter incorporates a layer of plasma forming particulate material supported optically in front of a sensor. A focussing means is positioned optically forward of the particulate layer to concentrate incident threat radiation on the particulate layer. The position of the particulate layer relative to the focussing means is selected such that the focal area encompassed by concentrated incident radiation encompasses a sufficient number of particulates to insure protective plasma formation and to insure that damage level incident radiation will be concentrated to an energy level exceeding the plasma formation threshold of the particulate material. The particulate layer is supported on a rotating window such that new areas of the layer can be exposed to incident radiation after a damage radiation incident.

Abstract: A radiation protection system is operative within an optical section of a radiation imaging system for protection of an array of detectors of the radiation. The protection system is formed of one or more spark boards arranged in series along a path of radiation propagation, the spark boards having a central window through which the radiation propagates. On a front side of each spark board are arranged a set of electrodes disposed about a periphery of the window. Ground pads are disposed on a back side of each board in registration with the electrodes on the front side to form therewith a set of capacitors. A capacitive-discharge power-supply circuit is connected to a first pair of electrodes in a first one of said boards. In the presence of excessive incident radiation power, a capacitor of the power supply circuit is switched to apply a high voltage across said first pair of electrodes, the voltage being high enough to initiate an arc across the window in said first board.

Abstract: A laser preionization electrode (15, 17) formed of a dielectric tube (16) of square cross-section enclosing an electrode (18) of circular cross-section, the electrode (18) being of a large diameter on the order of 6.35 millimeters. A pair of such electrodes (15, 17) are located on either side of a main electrode (11) in a laser with the result that longer length preionization electrodes may be constructed while eliminating alignment problems of the prior art.

Abstract: In an imaging system employing an array of detectors and an optical system for focusing rays of an image upon the detectors, there is provided a protection system in the form of a cell of gaseous lasing material disposed along a path of the imaging rays. A pair of electrodes and a supply of electric power induces an electric discharge through the lasing medium to heat the medium so as to enhance interaction between intense laser radiation which might inadvertently or deliberately, be directed toward the array of detectors. The laser radiation induces still further heating of the lasing medium with a resultant absorption of a relatively narrow frequency band of radiation, at the lasing frequency, so as to prevent damage to the array of detectors while allowing scene radiation outside of the narrow band to be received by the detectors.

Abstract: An improved railgap switch for use with pulse discharge gas lasers. The blade of the prior art railgap switches is replaced by an electrode having an "T" shaped cross section which provides two edges along which arcs are generated. The thickness of the "T" cross section near the edges at which arcs are formed is relatively uniform and oriented at a constant distance from the second electrode so that the thickness and distance remains unchanged despite ablation of the edges of the electrode. As a consequence the electrical properties of the switch are not altered significantly by ablation caused by repetitive operation of the switch.

Abstract: Apparatus is disclosed for protecting delicate sensor optics frm the damaging effects of unwanted powerful laser radiation. A thin-film reflective pellicle 14 is placed in the light path of a sensor telescope. Incident light 10 is focused by some combination of optical elements 12 onto the reflective surface 28 of the pellicle laser power limiter 14. The reflected light 10 is then imaged by further optics 16 onto a detector array 18. Should a signal too strong for the detector to enter the sensor aperture with the incident light 10, the focused power at the surface of the pellicle 28 will oblate the plastic and metallic film, burning a hole in the pellicle, and the high-power light 11 will be deflected from the detector array and instead will be absorbed by the beam dump 20. A power meter within the beam dump determines when the laser threat has stopped and signals the turning machanisms 15a and 15b to turn the pellicle reflector to a fresh position at which point normal sensor operations may resume.

Abstract: An improved electrical gap switch for use with pulsed gas discharge lasers. The closure of a spark gap, railgap, or other multichannel switch is triggered by the application of a second voltage in combination with the primary voltage that is closed by the switch. The second voltage is of opposite polarity and applied to an electrode opposite from that to which the primary voltage is applied. The second voltage has a more rapid rise time than that of the first, and its application to the switch is momentarily isolated from the load by a saturable inductor. Following triggering of the switch by the combination of voltages, the inductor saturates and provides a low impedance path for the voltage and charge from the primary source to the load.