Abstract: A device is disclosed which is capable of amplifying optical signals. The absorptive and dispersive properties of a cavity-enclosed nonlinear medium are combined with the transmission properties of the cavity to yield an input-output characteristic curve that displays gain or bistability.

Abstract: A laser having a radial flow configuration which may be utilized to achieve lasing in both chemically and electrically excited gas lasers.

Abstract: Gas laser generator comprising a gaseous active medium, at least one electric excitation line formed by an insulating plate inserted between a first and second metallic plate, the first plate having a slot enclosing the gaseous medium, a circuit for setting up a progressive current wave in the line. The plates are cut in the shape of superimposed half parabolas. A variant consists in producing the generator in the form of two half parabolas such as above but insulated from each other and brought to different potentials. The invention is implemented in high-power lasers.

Abstract: In a laser, a gaseous mixture is suitably heated to a first temperature and at a first pressure to provide a large energy content. The gaseous mixture comprises a polyatomic gas such as carbon dioxide having an upper level, ground state, and intermediate level. It also comprises at least one auxiliary gas such as nitrogen, having an energy level substantially resonant with one of the above-mentioned levels and a relaxation time operative to increase the ratio of the relaxation time of the upper level to that of the lower level. A chamber receives the mixture via a supersonic nozzle proportioned to provide a flow time short compared to the relaxation time of the upper level and long compared to the relaxation time of the lower level and the gas is throttled to a relative low second gas temperature and pressure, whereby population inversion exists in the chamber. An optical resonator defines a light path beam through the gaseous medium in the chamber.

Abstract: A gas laser tube has two regions, one characterized by a high electron temperature and the other by a low electron temperature. Included in the tube is means for establishing a space charge double sheath to separate the two regions. A mirror is located at each end of the region of low electron temperature.

Abstract: According to one herein disclosed embodiment, an initial uncompensated energy pulse is transmitted towards a remotely located target; a portion of the energy reflected from the target is received, processed so as to be back-scattered from a Brillouin mirror, amplified and then retransmitted along a path coincident with the received path. The backscattered energy from the Brillouin mirror is the complex phase conjugate of the received pulse and consequently the second transmitted pulse is phase encoded such that the effects of phase perturbations encountered along the received path are substantially canceled, and near diffraction-limited convergence of the beam upon the target is obtained.

Abstract: The invention concerns a device for treating a laser light pulse and comprises, aligned successively on a same axis, a polarizer, an optical rotator, semi-reflecting plates and a reflector. The device can be applied to high-power lasers.

Abstract: An electrically pumped gas laser with an electrode assembly providing for gas flow through spaced upstream and downstream electrode arrays with the flow path perpendicular to the optical axis of the laser in a very low inductance electrical circuit. Electrode arrays comprising parallel spaced blade shaped electrodes, with the upstream electrodes having a contoured leading edge and a trailing knife edge spaced from the walls of the discharge space, and with the downstream electrodes having a leading knife edge spaced from the walls of the discharge space and a similarly contoured trailing edge. An electrode assembly with upstream and downstream gas flow channels providing a double parallel plate transmission line for electrical connections and energy storage, with the channel walls serving either directly or as supporting structures for the inner plates, and with the outer plates in the form of conducting sheets spaced from the inner plates by insulating sheets.

Abstract: In the disclosed attenuation arrangement a plurality of axially extending boron nitride support rods having a substantially rectangular cross-section are disposed about the peripheral surface of a helical slow-wave structure. An attenuating coating is provided on the substantially radially extending opposing lateral surfaces of each rod, with the substantially circumferentially extending opposing lateral rod surfaces being free from attenuating material.

Abstract: A method and apparatus for obtaining laser action between an upper energy level and a lower energy level of a gaseous medium, which comprises populating the upper energy level to some degree (short of achieving a conventional inverted population) by any suitable pumping means, and thereafter establishing an inverted population by transiently and selectively depumping the lower energy level such as by exposing the medium to an intense source of radiation which selectively causes the transformation of the lower energy level species to some other energy level. Thus, a thermally pumped/optically depumped gas laser system is produced.

Abstract: A scanning device has mirrors which reflect a beam of light between them to pass successively through the lasing medium of a laser. The beam is slightly deflected on each path between the mirrors to scan a pattern and the beam is amplified with each passage through the laser. One mirror is partially reflective and partially transparent so the pattern determined by the reflective path of the light beam between the mirrors passes beyond the mirrors to be modulated for information storage, information retrieval, and other uses. One embodiment of the invention has two parallel mirrors with the beam slightly angled to be reflected back and forth along a row and wedge shaped deflectors fixed to the mirrors to shift the beam to another row so that the beam scans a pattern as it emerges from one of the partially transparent mirrors.

Abstract: A highly doped optical amplifier in the form of a thin layer or fiber wherein the pump light is directed transversely to the surface of the layer or fiber. A transparent substrate is provided underneath the layer or fiber and a solar cell is provided in light receiving relationship to light passing through the layer or fiber on the opposite side of the substrate.

Abstract: A laser device has a bore formed by aligned apertured carbon discs with the ratio of the pitch distance between adjacent discs to the diameter of the apertures through the discs being between 1.8 and 3.0. An optimum value of this ratio is 2.2. The pitch distance is the distance from one surface of a carbon disc to the corresponding surface on an adjacent disc; this distance being measured parallel to the bore axis. This relationship of aperture diameter to pitch distance substantially eliminates sputtering of the carbon discs and gas clean-up during laser operation.

Abstract: A TWT energizing circuit for compensating for the voltage droop at a TWT hode comprising the use of a differential amplifier which takes a modulation pulse at one of its inputs and a feedback signal comprising a sample of the body current from the TWT helix at the other of its inputs and applies a signal representative of the difference therebetween to the TWT grid. The above-described feedback circuit forces the grid voltage to track the cathode voltage thus maintaining a constant grid-cathode voltage drop.

Abstract: A laser which obtains lasing action from gases flowing into and out of a laser cavity is substantially improved by causing the flowing gases to traverse a strongly recirculating flow field. The recirculation of exhaust flow gases into the incoming flow gases, in a controlled recirculation region, leads to substantially uniform distribution of gas composition, chemical and thermodynamic states, pressure, temperature, density and refractive index throughout the cavity. Recirculation flow fields are generated by opposed jets, behind baffles, in swirling flow, in spheres when jet velocities are high and in duct flows where a high momentum, high velocity jet is surrounded by a co-flowing low momentum low velocity stream.

Abstract: A crystalline optical convertor, adapted to improve the efficiency of a resonant cavity of a laser cavity system, includes: neodymium ions used as lasing ions, a host for the neodymium ions which is used as a laser rod, convertor ions, and a crystalline convertor host. The convertor ions are selected from the group consisting of trivalent dysprosium and trivalent samarium. The crystalline convertor host is selected from the group consisting of: yttrium orthovanadate, yttrium phosphate, yttrium arsenate, yttrium chromate, gadolinium orthovanadate, gadolinium phosphate, gadolinium arsenate, gadolinium chromate and combinations thereof in solid solution. The convertor ions act as an activator for the crystalline convertor host. The combination of neodymium ions and neodymium host is arranged separate from the combination of the convertor ions and the convertor host.

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: A two-dimensional dye laser scanning system is provided wherein a dye laser having a controlled output wavelength is combined with a diffractive beam-bending device to produce a near infrared or visible laser beam that can be directed to scan in two orthogonal planes at 100 MHZ rates.

Abstract: A laser cavity containing a mixture of nitrogen, N.sub.2, and mercury, Hg, gas is optically pumped by a lamp containing mercury to produce a laser output of 546.1 nm. The upper laser level is excited through optical pumping by a resonance lamp while the lower level which is a low lying metastable state is depopulated by collisional quenching.

Abstract: A chemical laser including a laser pump which is relativey lightweight with no moving parts is provided. This produces a low pressure, regenerable, closed system for treating laser cavity exhaust gases to remove (i.e., pump) them from the system.The exhaust gases which emerge from the laser cavity of the chemical laser are pumped by reacting them preferably with titanium, titanium-zirconium alloys, zirconium, tantalum, etc. These gases include hydrogen, deuterium and their halides, the halogens, oxygen, CO.sub.2, nitrogen and H.sub.2 O. This obviates the requirements for heavy equipment normally employed to produce a high vacuum in the laser cavity.

Abstract: A device and method for synchronous generation and amplification of tunable UV laser radiation. The system makes use of flat plate conductors which contain first and second parallel spaced channels therein. In the first channel, a N.sub.2 discharge produces a N.sub.2 laser pulse which excites a dye cell laser that generates a narrow radiation spectrum. Optical grating dispersion elements select two tunable frequencies which produces a colinear two laser beam output. The two beam pulse is directed into a gas or vapor cell with a resonantly enhanced third order susceptibility which mixes the two frequencies and results in a vacuum ultraviolet signal. The signal from the gas or vapor cell is transmitted by a rotatable, movable mirror vacuum optical path, with variable pulse delay, to the second channel where it is injected into the discharge in the second channel at the instant that gain is available.

Abstract: The lasing species of CS(a.sup.3 .pi.) and CSe(a.sup.3 .pi.) are produced by reacting atomic carbon and COS or COSe in an inert medium such as helium, argon, nitrogen, etc.

Abstract: The disclosed distributed feedback laser employs an alkali halide crystal having a spatially modulated pattern of a stable color center and a complementary spatially modulated pattern of U-centers. The stability of the color centers is provided by initial additive coloration, conversion to U-centers, and subsequent reconversion; and the spatial modulation is provided by patterning the reconversion by exposing a portion of the crystal to an interference pattern of coherent light. Conversion occurs by two-photon absorption. The very large penetration depth and the use of ultraviolet frequencies that are only about one-half of the magnitude of the frequencies that would otherwise be required make this device and process attractive for thick holograms and for distributed feedback devices such as lasers.

Abstract: Broad, intermediate, and narrow field of view infrared telescopes, broad and narrow field of view visual telescopes, and a narrow field of view laser telescope, together with apparatus for boresighting said telescopes, all of the narrow field of view telescopes having a common objective lens with means for separating the optical pathways.

Abstract: A coupled cavity traveling-wave tube is disclosed wherein each interaction cavity has an oblong configuration in a plane perpendicular to the tube axis. The oblong cavities have a length-to-width ratio of a predetermined value between about 1.2 and 1.6, preferably being about 1.5. Coupling apertures in the end walls separating adjacent interaction cavities extend circumferentially about half way around aligned circular electron beam holes along the tube axis, with the circumferential extremeties of the coupling apertures lying substantially parallel to the length of the oblong interaction cavities.

Abstract: A laser assembly that includes a novel glass laser disc having an annular alkali lead borate glass coating for use in the assembly is disclosed. The annular coating has an index of refraction that is about 3 to 12% greater than the index of refraction of the laser disc, the thermal properties also being sufficiently matched with the glass laser disc so as to prevent the development of undesirable strains therein, the glass coating comprising a mixture of alkali metal oxides in which at least two different alkali metal oxides are present, and any K.sub.2 O that is present is limited to an amount of not substantially more than about 1% by weight and an effective energy absorbing amount of heavy metal oxide that absorbs energy at a wavelength of about 1.06 microns to prevent parasitic oscillations. The heavy metal oxides include oxides of transition metals of the 3d, 4d, 4f, 5d and 5f orbital series.

Abstract: Organic radical anions and cations are formed by passage of electric curr through compounds to be ionized in solution in an organic solvent and the anions and cations are allowed to combine to form excited molecular associations (exciplexes) in a laser resonator where they give up their excitation energy by stimulated emission of radiation to form a laser beam. The necessary ions can be excited with interelectrode voltages of the order of 3 to 10 volts. Aromatic hydrocarbons are used to produce anions and electron donor molecules such as para-tri-substituted triphenylamines (tri-p-tolylamine) to produce cations in solution in tetrahydrofuran or a tetrahydrofuran derivative. Excimer-forming aromatic hydrocarbons or derivatives and di-aryl alkanes can be used to produce both anions and cations that will form exciplexes capable of producing laser radiation.

Abstract: In a laser system activated by a molecular gas there is provided a novel nozzle construction for the purpose of effecting expansion of the gas in a minimum period of time but without destroying laminar flow conditions therein. Instead of the relatively long single nozzle of the prior art there is provided a plurality of nozzles expanding in three dimensional directions and arranged in parallel aligned relationship in a cluster closely adjacent each other. The nozzles may be of many cross-sectional shapes but in one embodiment the walls are concave, such that a relatively large wall angle with respect to the direction of flow at the throat of the nozzle diminishes progressively toward the end of the nozzle so that at such end the nozzle walls will be substantially parallel with each other, whereby to discharge the gas stream therefrom in a jet of constant cross-sectional area.

Abstract: A continuous wave chemical laser device in which useful species such as free radicals as vibrationally excited molecules are generated by interaction of suitable chemicals such as hydrogen, sulfur hexafluoride, and carbon dioxide with laser radiation. The chemical laser device is capable of generating active species by interaction of its own laser radiation after first being initiated by a suitable initiator. The chemical reactions involved can take place at atmospheric pressure or higher and overcome disadvantages of ordinary chemical lasers.

Abstract: Method for producing continuous wave chemical laser output in which useful species such as free radicals as vibrationally excited molecules are generated by interaction of suitable chemicals such as hydrogen, sulfur hexafluoride, and carbon dioxide with initiator laser radiation. The chemical laser output is sustained by feeding back a portion of the laser output after first being initiated by a suitable initiator. The chemical reactions involved can take place at atmsopheric pressure or higher and overcome disadvantages of ordinary chemical lasers.

Abstract: New 2,4,6 trisubstituted pyridines are useful as laser dyes. These dyes are used in solution with a non-interfering solvent to form lasing media useful in dye lasers. When excited, these dyes have emission wavelengths which cover the spectrum from 410-570 nm. The violet and near ultra-violet regions of the visible spectrum are particularly well-served by the new compounds.

Abstract: A multibeam laser amplifier system is disclosed wherein a plurality of laser beams may be amplified to high power with high efficiency. The beams may then be directed upon a target such as a nuclear fusion fuel element, as in a laser fusion reactor. The system is made up of an array of dual, active mirror laser amplifier units. The laser beams are reflected between successively disposed ones of these units. The units are optically pumped by flash lamps which are arranged in close proximity to the reflective sides of the laser bodies in each unit.

Abstract: A standard cavity, Q switched laser is used to initiate and sustain submicrosecond pulses in a long laser. Short pulses from the standard cavity laser are directed onto the remote reflector of a long laser and are then reflected back through the lasing material of the long laser. Properly timed activation of the long laser lasing material causes amplification and oscillation of the pulses in the long laser cavity. Beam expanding telescopes are used to focus the laser pulses on the long laser's remote reflector.

Abstract: The inventive laser comprises two identical hollow nozzle portions which are positioned in layered fashion (i.e., in stacked condition), in registration, and with their respective longitudinal axes in parallel. Each nozzle portion has a protrusion extending into the void or hollow interior, and coolant flow passages are located in the protrusion. The internal surface of each nozzle portion has a nickel fiber wick sintered to it, and the wick is saturated with a metal, preferably sodium, which is in a liquid state. The unique structure of the inventive nozzle permits a very short transient start and also permits operation of the nozzle at steady-state conditions in an isothermal manner.

Abstract: A miniature TEA laser system having a pair of electrodes mounted within the laser cavity and a radioactive source in the form of a beta particle emitter located within the cavity adjacent the electrodes. The electrodes are spaced no more than the maximum beta particle range apart so that the radioactive emission can take place within the space between electrodes thereby uniformly preionizing the active laser medium within the cavity.

Abstract: This device includes an expander open cycle gas dynamic laser wherein the majority of the gas dynamic laser flow is recirculated while a fraction of the flow is removed in a boundary layer bleed removal system. This device includes a combustor for providing the proper gas constituents which then flow downstream of a nozzle means in a laser cavity to permit lasing to occur. The flow from the lasing cavity is directed into a diffuser which in turn directs its flow into the inlet of a compressor after flowing over a heat exchanger which cools the flow. One heat exchanger is in the bleed flow while the other is in the flow from the diffuser. The flow from the compressor is directed into the combustor.

Abstract: Working gas for an electron beam discharge laser is generated by an airbreathing, hydrocarbon fuel burning, turbocompressor engine and shaft power of the engine may be utilized to drive a generator to provide electric power to the laser or to drive a compressor to put the turbocompressor exhaust gases in compressed storage for later use in the laser, either mode affording savings in weight and cost of operating materials and/or specific energy conversion efficiency compared to prior art, electric, chemical and gas dynamic laser systems.

Abstract: A method of producing a lasable gaseous mixture for use in and operation of electron beam-sustainer carbon dioxide lasers comprising burning a hydrocarbon fuel to produce substantially oxygen free products of combustion, removing undesirable constituents to leave a gaseous mixture which can support laser oscillation comprising substantially only carbon dioxide, nitrogen and hydrogen, collecting the resulting gaseous mixture, and thereafter supply and use it as the active medium in an electron beam-sustainer laser.

Abstract: A continuous working chemical laser is disclosed. A primary gas such as hydrogen or deuterium is mixed with an activator for a secondary gas, and desirably with a buffer such as a noble gas. The primary gas mixture and a secondary gas such as fluorine are mixed at low temperature and subsequently a laser emitting chemical reaction is triggered. In one embodiment the gases are mixed in supersonic flow and the reaction is triggered by a shock wave. In another embodiment the reaction is triggered by external stimulation such as ultraviolet radiation or electric discharge or the like.

Abstract: An efficient continuous wave solid state laser is described. An array of semiconductor diode lasers is employed to generate a pump light source at an absorption wavelength for a solid state laser such as Nd:YAG laser. The array of diode lasers is pulsed at a high repetition rate to produce narrow light pulses which are directed upon an end surface of the solid state laser rod. The pump pulses rate is selected sufficiently high to establish CW operation of the solid state laser while the duty cycle for the pump-light source is sufficiently low to avoid excessive junction heating of the diode lasers, which would substantially reduce their output power.

Abstract: A crossed-field device having a plurality of slow wave energy propagating structures, each with an associated cathode, requires relatively low voltage for operation to provide a high power output. Electron beam current control is achieved by means of RF drive signals. Periodic permanent magnet focusing is utilized.

Abstract: A coating consisting of polycrystalline Sm.sub.2 O.sub.3 powder dispersed in a Na.sub.2 SiO.sub.3 or K.sub.2 SiO.sub.3 binder may be provided on either the inner or outer lateral surface of a substantially tubular pumping cavity housing member for a Nd:YAG laser. The coating is absorptive of radiation at the lasing wavelength of about 1.06 .mu.m and has a thickness sufficient to provide a high diffuse reflectivity for pumping radiation.

Abstract: The members which are utilized to hold and position a rod of erbium laser glass material within an imaging cavity are formed of a glass material which is transparent at the pumping wavelengths of the erbium ions and/or associated sensitizer ions in order to prevent masking of the laser rod to the pumping light energy at those locations where the holders come into contact with the laser rod. This arrangement optimizes the performance of the erbium glass laser rod configuration.

Abstract: A gas laser is constructed of discrete segments in such a manner that the s flowing through the active region of the laser is introduced from a plenum chamber from whence it flows annularly into the active region and travels through the region both to the left and right of the input until it reaches the first output region. From there the gas flows annularly out into a shaping region and thence into the output plenum.

Abstract: In a high efficiency amplifier system a Traveling-Wave Tube (TWT) power amplifier is driven to saturated output by a second TWT (driver TWT) which is preferably but not necessarily operated at saturation. Broad band operation, over two octaves, is achieved by harmonic conditioning. In addition to the usual phase shifter harmonic conditioner, an interstage equalizer and an input equalizer are added. The attenuation vs. frequency characteristic of each of these two equalizers is properly proportioned to cause the driver TWT to develop a specific desired ratio between harmonic amplitude and fundamental amplitude output at each frequency. When a specific driver and power amplifier TWT were operated in a laboratory test and the two equalizers were adjusted for optimum fundamental output power, the interstage equalizer had maximum attenuation at the second harmonic frequency (relative to the low frequency end of the operating band) and the input equalizer had maximum attenuation at the third harmonic frequency.

Abstract: Laser amplifier of the type comprising a straight cylinder surrounded by a flash, characterized in that the cylinder comprises a first internal portion made of doped glass, having the shape of a cylinder of revolution whose shape is obtained by the rotation about an axis of an arc of a curve turning its convexity towards the axis and a second portion surrounding the first and whose component material is a liquid having an index close to that of the material constituting the first portion.

Abstract: The present invention relates to improved method and structure for producing an electric discharge in a laser cavity which eliminates arcing and permits electron energy to be chosen based on energy requirements for accelerating the electrons rather than energy and/or pressure requirements for supplying electrons. An auxiliary discharge is maintained to provide the electrons necessary for laser excitation. A transverse electric field is then superimposed to impart the energy required to accelerate the electrons.

Abstract: A gas laser emits an output laser beam from a low pressure region to a region having a higher pressure. This is done through an opening in the side of a laser device. Under normal circumstances, the provision of such an opening would incur a flow of air from the high pressure side, externally of the laser device, to the low pressure side within the device. To prevent this, an aerodynamic window is placed in a passageway leading from said opening in the laser device through which the laser beam passes. A gas flow is passed across said passageway which will provide a flow segment having a pressure differential across the segment which is equal to that between the low and high pressure regions. When such an aerodynamic window is used in an aircraft and the aircraft experiences changes in altitude, the pressure differential across the flow segment changes.

Abstract: An electrically pumped gas laser amplifier unit having a disc-like configuration in which light propagation is radially outward from the axis rather than along the axis. The input optical energy is distributed over a much smaller area than the output optical energy, i.e., the amplified beam, while still preserving the simplicity of parallel electrodes for pumping the laser medium. The system may thus be driven by a comparatively low optical energy input, while at the same time, owing to the large output area, large energies may be extracted while maintaining the energy per unit area below the threshold of gas breakdown.

Abstract: A gas laser emits an output laser beam from a low pressure region to a region having a higher pressure. This is done through an opening in the side of a laser device. Under normal circumstances, the provision of such an opening would incur a flow of air from the high pressure side, externally of the laser device, to the low pressure side within the device. To prevent this, an aerodynamic window is placed in a passageway leading from said opening in the laser device through which the laser beam passes. A gas flow is passed across said passageway which will provide a flow which represents the flow of a segment of a free-vortex flow field having a pressure differential across the segment which is equal to that between the low and high pressure regions. A single nozzle, specifically contoured to produce a segment of a free-vortex flow field directs the gas into the passageway and an opening collects the flow onto the other side of said passageway. A method of constructing such a nozzle is set forth.