Plural Active Media Or Active Media Having Plural Dopants Patents (Class 372/68)
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Patent number: 5388114Abstract: A diode-pumped monolithic laser is fabricated from a self-doubling host material co-doped with two ionic species, where one ionic dopant converts pump radiation to continuous radiation at a fundamental frequency and the other dopant acts as a saturable absorber to Q-switch the fundamental radiation which is then frequency doubled to produce pulsed high-intensity green light, the green light being either outputted or further frequency-doubled, into pulsed coherent UV radiation, by means of a non-linear crystal.Type: GrantFiled: March 17, 1994Date of Patent: February 7, 1995Assignee: Polaroid CorporationInventors: Joseph H. Zarrabi, Shobha Singh, Pavle Gavrilovic
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Patent number: 5386431Abstract: A slab laser amplifier array includes a plurality of parallel, stacked, laser resonators, with each resonator having a walk-off mode of propagation of laser light from an input side of the resonator to an output side of the resonator where the exiting light diffracts around the resonator mirror. A source of a plurality of phase related, for example co-phasal, light beams supplies phase related light to each input side. The source of phase related light may be a source of one single mode beam followed by a telescope with an aperture having plural stops or a co-phasal array of laser resonators. A laser array of open resonators also has circular concentric electrodes.Type: GrantFiled: June 7, 1993Date of Patent: January 31, 1995Inventor: John Tulip
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Patent number: 5375132Abstract: A pulsed solid state laser system is disclosed which utilizes a plurality of individual laser rods which are sequentially pumped and whose beans are combined into a single interleaved output bean. The individual laser rods are pumped at an average power level which is below that for maximum output power from each rod, thereby obviating the need for refrigeration cooling. A compact optical system is disclosed which permits a constant beam size even at different pump levels and other advantages. A compact cooling system is also disclosed.Type: GrantFiled: May 5, 1993Date of Patent: December 20, 1994Assignee: Coherent, Inc.Inventors: Kevin P. Connors, James L. Hobart, Edward D. Reed, David Trost, Kenneth J. Bossie, Thomas W. McCurnin, Gerald M. Mitchell, J. Michael Yarborough
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Patent number: 5373525Abstract: In order to improve a wave guide laser comprising a wave guide arranged between two resonator mirrors and having an outer cylindrical wave guide surface and an inner cylindrical wave guide surface facing the outer surface and arranged within this outer surface in spaced relation thereto, the two surfaces together forming a wave guide having a radiation coherent in the entire wave guide and essentially expanding in axial direction, and a high-frequency excited and diffusion-cooled laser gas arranged between the wave guide surfaces, such that the high-power Laser beam can be outcoupled by an element which is constructionally simple to produce and inexpensive, it is suggested that the second resonator mirror be composed in azimuthal direction of a plurality of successive reflecting segments, that outcoupling openings for the laser radiation to be outcoupled be provided between the respective reflecting segments and that the entire radiation expanding in the wave guide be diffraction-coupled in azimuthal directioType: GrantFiled: January 29, 1993Date of Patent: December 13, 1994Assignee: Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V.Inventors: Rolf Nowack, Hans Opower
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Patent number: 5369657Abstract: A silicon-based microlaser formed of rare-earth-doped CaF.sub.2 thin films has a semiconductor substrate material (240) and a CaF.sub.2 film layers (234) grown on semiconductor substrate material (240), The CaF.sub.2 film layer (234) is doped with a predetermined amount of rare-earth-dopant that is sufficient to cause a spectral emission from the CaF.sub.2 film layer (234) having a narrow linewidth when the CaF.sub.2 film layer (234) is optically or electrically pumped.Type: GrantFiled: September 15, 1992Date of Patent: November 29, 1994Assignee: Texas Instruments IncorporatedInventors: Chih-Chen Cho, Walter M. Duncan
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Patent number: 5365538Abstract: A slab waveguide pumped channel waveguide laser includes a slab waveguide having a primary pump guiding layer with a first index of refraction and having first and second opposing faces and a peripheral edge including a mirrored surface, and cladding means having a second index of refraction lower than the first index of refraction, proximate the first and second opposing faces; at least one rare earth doped channel waveguide laser having a third index of refraction higher than the first index of refraction disposed in the primary guiding layer; and means for introducing pumping energy into the guiding layer to reflect between the mirror surfaces and energize the laser.Type: GrantFiled: October 29, 1992Date of Patent: November 15, 1994Assignee: The Charles Stark Draper Laboratory Inc.Inventors: Richard Tumminelli, Farhad Hakimi, John R. Haavisto
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Patent number: 5341389Abstract: Yb.sup.3+ and Nd.sup.3+ doped Sr.sub.5 (VO.sub.4).sub.3 F crystals serve as useful infrared laser media that exhibit low thresholds of oscillation and high slope efficiencies, and can be grown with high optical quality. These laser media possess unusually high absorption and emission cross sections, which provide the crystals with the ability to generate greater gain for a given amount of pump power. Many related crystals such as Sr.sub.5 (VO.sub.4).sub.3 F crystals doped with other rare earths, transition metals, or actinides, as well as the many structural analogs of Sr.sub.5 (VO.sub.4).sub.3 F, where the Sr.sup.2+ and F.sup.- ions are replaced by related chemical species, have similar properties.Type: GrantFiled: June 8, 1993Date of Patent: August 23, 1994Assignee: The United States of America as represented by the United States Department of EnergyInventors: Stephen A. Payne, Wayne L. Kway, Laura D. DeLoach, William F. Krupke, Bruce H. T. Chai
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Patent number: 5341237Abstract: The effective rate of deactivation from the terminal state to the ground state of a rare earth ion doped optical material in a four-level amplifying or lasing scheme may be increased greatly by doping the optical material with two rare earth ions, an activator and a deactivator. Energy transfer occurs between the terminal state in the activator ion and the deactivator ion. The transition from the deactivator to the ground state occurs via phonon emission. By increasing the deactivation rate, the efficiency of the laser and the amplifier is increased.Type: GrantFiled: January 31, 1992Date of Patent: August 23, 1994Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Genji Tohmon, Hisanao Sato, Toshihiro Fujita, Jun Ohya
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Patent number: 5299215Abstract: An upconversion laser system that uses solid state components throughout and achieves such operation with a continuous or quasi-continuous single band infrared pumping source using successive energy transfers between the sensitizer and activator in the host of the lasant upconversion material.Type: GrantFiled: September 25, 1991Date of Patent: March 29, 1994Assignee: Amoco CorporationInventors: Robert J. Thrash, Leo F. Johnson
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Patent number: 5289482Abstract: In a preferred embodiment, a Tm.sup.3+ :YAG laser crystal and a Ho.sup.3+ :YAG laser crystal are placed within a reflective path of a laser cavity for intracavity pumping the Ho.sup.3+ :YAG laser crystal. The Tm.sup.3+ :YAG laser crystal emits a substantially 2.0 .mu.m laser emission after being resonantly end-pumped by a pump beam at a wavelength of about 785 nm and the substantially 2.0 .mu.m laser emission is used to pump the Ho.sup.3+ :YAG laser crystal. The intracavity-pumped Ho.sup.3+ :YAG laser crystal emits an output laser emission at substantially 2.1 .mu.m. The slope efficiency of the Ho.sup.3+ :YAG laser crystal output power is about 40% of the pump power absorbed by the Tm.sup.3+ :YAG laser crystal.Type: GrantFiled: December 30, 1992Date of Patent: February 22, 1994Assignee: The United States of America as represented by the Secretary of the NavyInventors: Leon Esterowitz, Robert S. Stoneman
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Patent number: 5289490Abstract: The present invention relates to a solid state laser generation apparatus which is composed of modularized solid state lasing units which enable construction of a compact cascading laser apparatus having a low lasing threshold value and a high laser generation efficiency. A lasing rod and the electrodes for the excitation of the rod are housed in a common module casing which has depressed sections on its external surface. When assembling two modular units, one of the module units is rotated axially with respect to the other in such a way to insert the electrodes into the depressed section on the external surface of the neighboring module so as to minimize the mechanical interference caused by the neighboring components. By utilizing such a modular arrangement, the lasing rod spacing between the neighboring module units can be shortened, thus resulting in lower coupling losses between the adjacent rods even during the initial phase of the operation.Type: GrantFiled: September 2, 1992Date of Patent: February 22, 1994Assignee: Ishikawajima-Harima Heavy Industries Co., Ltd.Inventors: Yoshito Taniu, Mikinori Shono, Koichiro Wazumi, Akihiro Nishimi
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Patent number: 5287378Abstract: The directly pumped holmium (Ho) quasi-two level laser of the invention comprises a directly pumped holmium laser having a host material doped with an amount of holmium ions sufficient to produce an output laser emission at a wavelength of about 2.1 .mu.m when the holmium laser is pumped by a pump beam at a wavelength of about 2 .mu.m and a pumping laser for producing the pump beam. In an exemplary embodiment, the pumping laser comprises a Cr,Tm:YAG laser pumped by a flashlamp.Type: GrantFiled: December 30, 1992Date of Patent: February 15, 1994Assignee: The United States of America as represented by the Secretary of the NavyInventors: Steven R. Bowman, Barry J. Feldman
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Patent number: 5285467Abstract: Efficient, low threshold laser emission from a laser crystal doped with chromium and neodymium ions is obtained when pumped by visible laser diodes in the range of 610 nm to 680 nm. A typical laser Cr,Nd:GSGG crystal having an extraordinarily broad absorption bandwidth allows high pump efficiencies when using visible laser diodes, particularly in comparison to the Nd:YAG laser. The broad absorption bandwidth tolerance of the Cr,Nd:GSGG crystal to the pumping wavelengths allows visible diode pumping of the neodymium transition without regard to the wavelength of the visible diodes. Longitudinal or end-pumping to take advantage of the emission properties of the visible laser diodes, a nearly hemispherical laser resonator configuration and other co-doped Cr,Nd laser host materials are disclosed. Consequently, costs are reduced for the semiconductor pump as well as producing a compact, efficient, lightweight and reliable laser previously unachievable with other types of laser or lamp pumping.Type: GrantFiled: February 22, 1993Date of Patent: February 8, 1994Assignee: The United States of America as represented by the Secretary of the NavyInventor: Richard Scheps
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Patent number: 5282079Abstract: An Ar.sup.+ ion laser pumped optical fibre amplifier is provided with an optical fibre having a core which has been solution doped using a solution of an aluminum and an erbium salt.Type: GrantFiled: July 2, 1992Date of Patent: January 25, 1994Assignee: Pirelli General plcInventors: Richard I. Laming, Simon B. Poole
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Patent number: 5274650Abstract: A solid state laser provided with a pair of mirrors constituting a laser resonator and a plurality of non-linear optical crystals placed between the pair of mirrors in such a manner to have an optical axis in common therewith and a pump source for irradiating pump light on the plurality of non-linear optical crystals. In the solid state laser, the non-linear optical crystals are operative to generate both of fundamental-wave laser light and harmonic laser light in response to the pump light.Type: GrantFiled: December 27, 1991Date of Patent: December 28, 1993Assignee: Hoya CorporationInventor: Satoru Amano
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Patent number: 5272713Abstract: A pulsed laser system capable of operating at higher repetition rates, while maintaining the efficiency and beam quality of the output pulses comprises first and second gain media with one or more pump energy transducers, such as flashlamps, coupled with each of the gain media. A power supply generates a first sequence of pulses of input power and a second sequence of pulses of input power which drive respective subsets of the pump energy transducers in an independent timing relationship. Thus, two non-aligned 50 Hz sequences of input pulses which are interleaved generate an output pulse stream at 100 Hz from the laser system with the efficiency, beam quality, and average power comparable to that of a 50 Hz laser. By pumping subsets of the pump energy transducers coupled to a laser system in an interleaved fashion, higher repetition rates may be achieved with better output beam quality and higher average power than has been obtainable with prior art systems.Type: GrantFiled: August 27, 1992Date of Patent: December 21, 1993Assignee: Spectra-Physics Lasers, Inc.Inventors: Mark S. Sobey, Bertram C. Johnson, Glen R. Blevins
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Patent number: 5243615Abstract: Power output and power conversion efficiency of an intracavity non-linear optical laser is substantially increased by reducing the effect of thermal focussing per unit of pump energy enabling a stable resonator cavity at high input powers by utilizing a closely coupled reflector, multi-gain media configuration, and various pump source filters and/or semiconductor laser diode pumping.Type: GrantFiled: November 20, 1991Date of Patent: September 7, 1993Assignee: LaserscopeInventors: Mark V. Ortiz, Dirk J. Kuizenga, Steven C. Murray, John H. Fair
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Patent number: 5200972Abstract: The 1.06.mu. Nd transition in a co-doped Cr,Nd:Gd.sub.3 Sc.sub.2 Ga.sub.3 sub.12 (Cr,Nd:GSGG) gain element is obtained by diode pumping Cr.sup.3+ at 670 nm and produces efficient, low threshold laser operation. Although co-doped Cr,Nd:GSGG was developed for more efficient flashlamp pumping, it has the desirable property of having an extraordinarily broad absorption to allow for efficient diode pumping relative to the Nd:YAG laser. The consequent broad bandwidth tolerance of the Cr,Nd:GSGG for the diode pumping radiation allows diode pumping of the 1.06.mu. transition without regard to the wavelength of the visible diodes which has the potential for reducing the cost of the semiconductor pump and also demonstrates the extended versatility of these diodes which previously had been restricted to pump the Cr.sup.3+ tunable vibronic lasers. CW and long pulse diode pumping provided pump power levels as high as 300 mW cw and 1 W pulsed. The lowest threshold power was measured at 938 .mu.Type: GrantFiled: June 17, 1991Date of Patent: April 6, 1993Assignee: The United States of America as represented by the Secretary of the NavyInventor: Richard Scheps
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Patent number: 5182759Abstract: A laser apparatus and method is disclosed comprising a first lasant material which is located in an optical cavity and which produces laser radiation of a first wavelength, and a second lasant material which is pumped by radiation from the first lasant material, which absorbs laser radiation at the first wavelength in an amount generally comparable to the Optimum Output Coupling, which functions as the output coupler for the optical cavity and which lases at a second wavelength. The first lasant material and the second lasant material are preferably selected to have minimal losses such that there is a net gain in the cavity.Type: GrantFiled: September 17, 1991Date of Patent: January 26, 1993Assignee: Amoco CorporationInventors: Douglas W. Anthon, John H. Clark, Leo Johnson, Timothy J. Pier
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Patent number: 5172387Abstract: This invention forces a multi-spectral line laser to operate on a single spectral line by modifying the gain of the medium instead of the standard approach of modifying the loss of the cavity. The spectral line selected by the system of the present invention is always the same identical spectral line. There are no ambiguities in knowing which line has been selected as there are with other methods. The invention involves a system for using more than one type of gain media within the laser cavity. Each medium gives rise to a distinct set of spectral line frequencies at which it has gain. Only occassional coincidences will occur at which spectral lines from two or more media fall within a linewidth of each other. Where these coincidences do not occur, the gain for a spectral line is only proportional to the amount of the individual medium present and will be below threshold.Type: GrantFiled: May 28, 1991Date of Patent: December 15, 1992Assignee: Hughes Aircraft CompanyInventor: David Fink
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Patent number: 5157674Abstract: A method for preparing a material so as to exhibit second harmonic generan for optical radiation that passes through the material. The method includes a first step of providing a bulk glass comprised of substitutionally doped silica and a charge transfer dopant. The bulk glass is prepared for frequency doubling in accordance with a method that includes a step of irradiating the bulk glass with optical radiation having a first wavelength and a second wavelength, the bulk glass being irradiated for a period of time sufficient to obtain a desired amount of conversion efficiency of the first wavelength into the second wavelength. The silica is substitutionally doped with an element selected from the group consisting of Ge and Al, and the charge transfer dopant is selected from the group consisting of Ce.sup.3+, Nd.sup.3+, and Eu.sup.2+. In another embodiment of the invention the silica is substitutionally doped with Ge and the charge transfer dopant is comprised of naturally existing Ge defects.Type: GrantFiled: June 27, 1991Date of Patent: October 20, 1992Assignee: Intellectual Property Development Associates of Connecticut, IncorporatedInventor: Nabil M. Lawandy
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Patent number: 5148445Abstract: A high power TEM.sub.00 mode Nd:YLF solid state laser includes at least two pumped Nd:YLF solid state rods in series within a laser resonator. A spherical lens may be incorporated within the resonator as required for establishing, in concert with the rods and resonator end mirrors, a large intracavity beam diameter at the position of the rods. A cylindrical lens may be provided to compensate for astigmatic thermal focusing of the Nd:YLF rods, or else the rods may be used in pairs, in which case the rods are rotated by 90.degree. about the laser axis with respect to each other, and a half-wave plate is inserted between the rods of each pair to maintain oscillation at a single wavelength.Type: GrantFiled: September 26, 1990Date of Patent: September 15, 1992Assignee: Quantronix Corp.Inventors: Kuo-Ching Liu, Sten Tornegard, Michael Rhoades
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Patent number: 5140598Abstract: An optical fiber doped with Er is provided at its both end portions with a pair of 1.25 .mu.m band reflecting filters such that the distance therebetween becomes the resonator length for a light beam of 1.25 .mu.m band. When a pumping light beam of a wavelength of 0.8 .mu.m band is introduced into the optical fiber, laser oscillation at 1.25 .mu.m band is produced, whereby the energy level of Er in an excited state is lowered and a signal light beam of a wavelength of 1.55 .mu.m band can be optically amplified with high efficiency. Another fiber optic amplifier in which a pair of 0.98 .mu.m band reflecting filters are disposed at both end portions of an optical fiber doped with Yb and Er such that the distance therebetween becomes the resonator length for a light beam of 0.98 .mu.m band is also disclosed.Type: GrantFiled: May 17, 1991Date of Patent: August 18, 1992Assignee: Fujitsu LimitedInventors: Kenji Tagawa, Shinya Inagaki, Keiko Takeda
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Patent number: 5134626Abstract: A solid laser generator employing a flash light as light source for excitation and titanium-doped sapphire as laser medium, wherein cerium and/or erbium-doped quartz glass, transparent plastic or transparent ceramic, is disposed in the vicinity of the laser medium or in the vicinity of the flash lamp.Type: GrantFiled: September 13, 1990Date of Patent: July 28, 1992Assignee: Tosoh CorporationInventors: Seiji Oda, Nobuhiro Kodama
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Patent number: 5121400Abstract: Device for coherent addition of laser beams including several optical amplifiers in parallel pumped by a beam coming from a master laser. The beams emitted by these amplifiers are transmitted to a non-linear material and play the role of pump beams. The non-linear material also receives a signal beam derived from the master laser. The various beams of the amplifiers are therefore added in the non-linear material along the direction of the signal beam.Type: GrantFiled: November 30, 1990Date of Patent: June 9, 1992Assignee: Thomson-CSFInventors: Jean-Marc Verdiell, Jean-Pierre Huignard, Henri Rajbenbach
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Patent number: 5115444Abstract: A switchable multichannel external cavity injection laser incorporates a diffraction grating between a linear array of n reflectors and a common reflector to define a set of n optical cavities having different frequency bands. Each of the (n+1) reflectors is provided by the optically distal end of an associated semiconductor laser amplifier whose optically proximal end is arranged to be substantially non-reflective.Type: GrantFiled: December 11, 1990Date of Patent: May 19, 1992Assignee: STC PLCInventors: Paul A. Kirkby, Ian H. White
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Patent number: 5107538Abstract: It has been discovered that co-doping of Er-doped Si with a light element such as C, N or F can result in substantially increased Er luminescence. A further increase in luminescence can result if, in addition, oxygen is present in the Si. Apparatus or systems according to the invention comprise a device (e.g., laser, optical ampifier, LED) that comprises a planar waveguide whose core region contains, in addition to at least 90 atomic % Si or SiGe alloy, Er, Pr and/or Nd, and further contains C, N and/or F, and preferably also contains oxygen. Currently preferred apparatus or systems according to the invention comprise means for electrically pumping the waveguide means.Type: GrantFiled: June 6, 1991Date of Patent: April 21, 1992Assignee: AT&T Bell LaboratoriesInventors: Janet L. Benton, Dale C. Jacobson, Lionel C. Kimerling, Jurgen Michel, John M. Poate
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Patent number: 5088103Abstract: A room temperature solid state laser for producing a laser emission at a wavelength of substantially 2.09 microns is disclosed. In a preferred embodiment, the laser includes: a laser cavity defined by first and second reflective elements opposing each other on a common axis to form a path therebetween; a laser crystal disposed in the laser cavity, the laser crystal having a host material capable of accepting Cr.sup.3+ sensitizer ions, Tm.sup.3+ sensitizer ions and Ho.sup.3+ activator ions; an amount of Cr.sup.3+ sensitizer ions between about 0.3% and about 2% dispersed within the host material; an amount of Tm.sup.3+ sensitzer ions between about 3% and about 12% dispersed within the host material; and an amount of Ho.sup.3+ activator ions between about 0.1% and about 0.7% dispersed within the host material; and flashlamp and means for exciting the laser crystal to produce a laser emission at substantially 2.09 microns with a slope efficiency of at least 4%, and preferably of at least 5%.Type: GrantFiled: April 30, 1990Date of Patent: February 11, 1992Assignee: The United States of America as represented by the Secretary of the NavyInventors: Leon Esterowitz, Gregory J. Quarles
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Patent number: 5077751Abstract: A pumped laser arrangement comprises a pumping laser and at least first and second laser elements positioned such that their axes intersect at a predetermined angle. A mirror which transmits light emitted by the pumping laser and reflects light emitted by the laser elements is positioned at the intersection of the axes to reflect light between the ends of the first and second laser elements. The pumping laser is optically coupled through the mirror to the end of one of the first and second laser elements.Type: GrantFiled: June 29, 1989Date of Patent: December 31, 1991Assignee: NEC CorporationInventors: Shuetsu Kudo, Shuichi Watanabe
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Patent number: 5077750Abstract: Disclosed is a power laser in which several laser diodes emit pump beams towards amplifier media. The beams coming from these amplifier media are combined by an optical system to give a common beam transmitted to an output mirror. The mirror and a reflecting face of each amplifier forms an optical cavity.Type: GrantFiled: May 24, 1990Date of Patent: December 31, 1991Assignee: Thompson-CSFInventors: Jean-Paul Pocholle, Michel Papuchon
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Patent number: 5070507Abstract: A laser system is disclosed wherein neodymium laser is used to pump a holmium laser to produce a moderately high energy output pulse at about 3 microns. The holmium host has a concentration of holmium in execess of 15 percent and a praseodymium concentration of at least 0.005 percent.Type: GrantFiled: March 2, 1990Date of Patent: December 3, 1991Assignee: Amoco CorporationInventor: Douglas W. Anthon
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Patent number: 5056096Abstract: An hybrid laser source has a ring structure including the optical path in a semiconductor amplifier chip (1) and optical fibres (2, 3 and 4). The fibre (2) is rare-earth doped and provides an additional gain medium in the ring, the chip providing its own gain medium. The two gain media are interactive and when the chip input current is modulated the source produces relatively high peak power ultrashort pulses (FIG. 1).Type: GrantFiled: September 17, 1990Date of Patent: October 8, 1991Assignee: STC PLCInventors: Robert A. Baker, Wilson Sibbett, David Burns
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Patent number: 5052013Abstract: A pulsed source of laser light (10) includes a diffraction grating (20) that splits light received from a laser output mirror (12) into a plurality of paths that lead to respective laser gain cells (14.sub.1, 14.sub.2, . . ., 14.sub.n). The gain cells individually amplify light components of different respective wavelengths and reflect them back to the diffraction grating (20), which reassembles them into a single beam for transmission to the laser output mirror (12). A mode locker (24), preferably in the form of a saturable absorber, locks the output components into equally spaced frequencies so that the sum of the individual continuous components will be a pulsed signal.Type: GrantFiled: April 20, 1990Date of Patent: September 24, 1991Inventor: Roger S. Putnam
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Patent number: 5048030Abstract: A light amplifying device comprising an optical oscillator constituted by first and second reflective mirrors and a common reflective mirror disposed in an optically opposite relation to each other, a polarized beam splitter for making a laser beam incoming from the side of the common reflective mirror incident on the first or second reflective mirror, and for making laser beams incoming from the sides of the first and second reflective mirrors incident on the common mirror, first and second amplifying media disposed in optical paths of the respective laser beams for amplifying the laser beams, and an optical element for rotating the polarizing plane of the laser beam reflected by the common reflective mirror by a predetermined angle.Type: GrantFiled: March 14, 1991Date of Patent: September 10, 1991Assignee: Fuji Photo Film Co., Ltd.Inventor: Hiroyuki Hiiro
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Patent number: 5038353Abstract: A laser system employing thulium and holmium in a trivalent state. The quantum levels of interest in the thulium and holmium are coupled so that one pumping photo absorbed by the thulium results in two photons emitted by the holmium, making for an unusually efficient laser system. The lower level is sufficiently depopulated at room temperature to allow laser operation without cryogenics. In preferred embodiments, the laser pump can be a laser diode, itself especially efficient, and whose output frequency is closely matched in photon energy to the thulium quantum state of interest, thus lending additional efficiency to the overall system. The thulium and the holmium exist in an yttrium-aluminum garnet crystal as lattice replacements for yttrium.Type: GrantFiled: February 21, 1990Date of Patent: August 6, 1991Assignee: The United States of America as represented by the Secretary of the NavyInventors: Leon Esterowitz, Roger E. Allen, Gregory J. Kintz
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Patent number: 5018163Abstract: A laser oscillator system which transmits laser input beam pulses through optical diode and into a plurality of time-multiplexed phase conjugate amplifier which sequentially amplify in chronological order subsequent input beam pulses. The optical diode is positioned on the oscillator laser beam pulse axis and is comprised of a polarizer, a half-wave plate which rotates the pulse polarity by 45.degree. in one direction and a Faraday rotator which rotates the pulse polarity 45.degree. in the opposite direction. A plurality of grouped Pockels cells and polarizers are positioned on the oscillator axis past the Faraday rotator. The polarizers route the input beam pulse toward a phase conjugate amplifier when a half-wave voltage is applied to the Pockels cell. Each phase conjugate amplifier has a phase conjugate mirror, at its output for retroreflecting the once amplified input laser beam pulse back therethrough for a second amplification.Type: GrantFiled: April 26, 1990Date of Patent: May 21, 1991Assignee: The United States of America as represented by the Secretary of the ArmyInventors: Geraldine H. Daunt, Richard A. Utano, Suresh Chandra
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Patent number: 5001718Abstract: In order to compensate for the thermally induced lens in the active element of an optical stage of a laser, the optical stage is provided with a telescope. The telescope comprises first and second lens arrangements. The first lens arrangement is located so that thermally induced lens is located at one of its focal planes. The position of the second lens arrangement is adjusted so as to compensate for variations in the power of flashlamps which pump the active element. In one embodiment, the laser has an oscillator stage and an amplifier stage. The telescope is placed after the oscillator stage and comprises two convex lenses.Type: GrantFiled: May 29, 1990Date of Patent: March 19, 1991Assignee: Lumonics, Ltd.Inventors: Graham Burrows, James M. Burch
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Patent number: 4998259Abstract: A laser oscillator system which transmits laser input beam pulses through a olarizer onto the surface of a rotating mirror which routes the laser beam pulses sequentially into a plurality of stationary phase conjugate amplifiers. The pulse repetition frequency of the oscillator input beam pulses is much higher than any one of the amplifiers can handle without overheating. The amplifiers are positioned in a circle around the laser oscillator axis. The polarizer and rotating mirror are positioned on the oscillator axis. The mirror is synchronized with the input beam pulses so that each subsequent input beam pulse enters the next amplifier in sequence. Each phase conjugate amplifier has associated therewith a quarter-wave plate and a phase conjugate mirror at its output. The phase conjugate mirror is preferably comprised of a focusing lens and a stimulated Brillouin scattering cell.Type: GrantFiled: March 29, 1990Date of Patent: March 5, 1991Assignee: The United States of America as represented by the Secretary of the ArmyInventors: Suresh Chandra, Geraldine H. Daunt
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Patent number: 4969154Abstract: A room temperature solid state laser for producing a laser emission at a wavelength of substantially 2 microns is disclosed. In a preferred embodiment, the laser comprises: a laser crystal having a host crystal material doped with an effective percent concentration of CR.sup.3+ sensitizer ions and with an effective percent concentraton of Tm.sup.3+ activator ions; and a flashpump for exciting the laser crystal to produce a laser emission at substantially 2 microns at a slope efficiency of at least 2 percent.Type: GrantFiled: December 22, 1989Date of Patent: November 6, 1990Assignee: The United States of America as represented by the Secretary of the NavyInventors: Leon Esterowitz, Gregory J. Quarles, Charles L. Marquardt
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Patent number: 4956843Abstract: The output of a single semiconductor light source is used to optically pump two solid state lasers which are arranged in series and produce laser radiation at two different frequencies. Single longitudinal and single transverse mode operation can be achieved in both lasers.Type: GrantFiled: October 10, 1989Date of Patent: September 11, 1990Assignee: Amoco CorporationInventors: Pedram Akhavan-Leilabady, Douglas W. Anthon
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Patent number: 4955036Abstract: A device for the amplification of light including a periodic semiconductor structure composed of different layers extending in the propagation direction of the optical wave. The periodic structure is constructed of a series connection of at least two semiconductor materials having the band gaps E1 and E2 and the refractive indices n1 and n2 (e.g., E1<E2, n1>n2), can be operated as follows:as a passive interference filter;as an active, partially amplifying interference filter;as a narrow band optical amplifier;as a single-mode laser which emits only a single mode.Type: GrantFiled: March 17, 1989Date of Patent: September 4, 1990Assignee: Alcatel N.V.Inventor: Albrecht Mozer
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Patent number: 4942586Abstract: A single cavity laser device comprises a diode pumped laser medium having a relatively high gain but a relatively low power. With this medium, a control laser beam is generated. Also positioned in the cavity is a second laser medium having a relatively large gain volume which is pumped by an array of laser diodes at a relatively low gain to create a reservoir of excited state ions. Positioned between these two diode pumped laser mediums is a beam expander which focuses the control laser beam onto the second laser medium to substantially fill the gain volume of the second laser medium. Stimulation of the excited ions in the gain volume of the second laser medium by photons in the control beam efficiently generates a laser beam of relatively high power.Type: GrantFiled: April 25, 1989Date of Patent: July 17, 1990Assignee: Intelligent Surgical Lasers Inc.Inventor: Shui T. Lai
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Patent number: 4922502Abstract: In a solid-state laser device comprising a slab-shaped laser medium, first through n-th excitation units are arranged on the slab-shaped laser medium to define first through n-th partial zones and to generate first through n-th laser beams from the first through n-th partial zones along optical axes, respectively. In order to selectively energize the first through n-th excitation units, a reference light beam is previously generated by a beam generator to be delivered through a fixed mirror and a beam distributor to a selected one of the first through n-th partial zones. Thereafter, the reference light beam travels through the slected partial zone to be received by a photosensor. The photosensor detects the selected partial zone to energize a selected one of the first through n-th excitation units that is made to correspond to the selected partial zone.Type: GrantFiled: June 29, 1988Date of Patent: May 1, 1990Assignee: Hoya CorporationInventors: Josef F. Unternahrer, Hiroshi Sekiguchi
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Patent number: 4910746Abstract: A multiple crystal, single pumping cavity laser system comprises an optical pumping cavity, several laser crystal rods disposed in the cavity and having differently sized diameters and with their axes parallel, an optical coupling device for coupling the rods in a chain of increasing diametrical size, an optical pumping source for providing an optimum pumping level for the largest rod, and attenuators for all but the largest sized rod for attenuating the energy absorbed by the smaller rods. Since all of the laser rods are disposed and pumped in a single pumping capacity, only a single pumping source is required. The housing containing the pumping cavity is thermally and mechanically isolated from the rail holding the other system components to prevent shock from being transmitted to the other components.Type: GrantFiled: November 9, 1988Date of Patent: March 20, 1990Inventor: Peter Nicholson
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Patent number: 4881238Abstract: In a well-known semiconductor laser, a multiple quantum well type active layer consisting of barrier layers and active layers or well layers, each of which has a thickness less than the de Broglie wavelength of electrons, is doped with an impurity, and the impurity density is made higher in the barrier layer than in the well layer. Further, in a case where the multiple quantum well active layer is held between p-type and n-type cladding layers, the well layer is undoped, the part of the barrier layer lying in contact with the well layer is undoped, and the other part of the barrier layer close to the p-type cladding layer is put into the n-conductivity type while that of the barrier layer close to the n-type cladding layer is put into the p-conductivity type.Type: GrantFiled: July 22, 1986Date of Patent: November 14, 1989Assignee: Hitachi, Ltd.Inventors: Naoki Chinone, Kazuhisa Uomi, Tadashi Fukuzawa, Hideaki Matsueda, Takashi Kajimura
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Patent number: 4876694Abstract: This invention relates to an external cavity slab laser system for pulsed or continuous wave operation consisting of an optically excited, water cooled single or multiple active mirror slab configurations with the external cavity formed by the active mirror and a passive mirror set parallel to each other and separated from each other by a distance greater than the thickness of the slab. Laser beams of both circular and elliptical cross-section can be amplified by the invention which has application in medical apparatus, industrial workstations and defense systems.Type: GrantFiled: December 23, 1988Date of Patent: October 24, 1989Assignee: Advanced Lasers LimitedInventor: John L. Hughes
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Patent number: 4860303Abstract: The solid metal current return in a typical commercial co-axial flashlamp replaced with a light transmissive current return which permits light from either or both surfaces of the flashlamp to be used to pump dye volumes. This enables one flashlamp to pump two dye volumes simultaneously, resulting in a significant increase in the overall efficiency of the co-axial flashlamp-pumped dye laser.Type: GrantFiled: January 17, 1989Date of Patent: August 22, 1989Assignee: The United States of America as represented by the Secretary of the ArmyInventor: Stephen D. Russell
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Patent number: 4860301Abstract: A multiple crystal, single pumping cavity laser system comprises an optical pumping chamber, several laser crystal rods disposed in the chamber and having differently sized diameters and with their axes parallel, an optical coupling device for coupling the rods in a chain of increasing diametrical size, an optical pumping source for providing an optimum pumping level for the largest rod, and attenuators for all but the largest sized rod for attenuating the energy absorbed by the smaller rods. All of the laser rods are disposed and pumped in a single pumping chamber. The housing containing the pumping chamber is thermally and mechanically isolated from the rail holding the other system components to prevent shock from being transmitted to the other components.Type: GrantFiled: December 3, 1986Date of Patent: August 22, 1989Inventor: Peter Nicholson
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Patent number: 4819246Abstract: A single frequency adapter for a gas laser comprises a jacket for engaging and being secured to the casing surrounding the gas laser. An induction coil is fixed within the jacket and positioned to surround the hollow mirror mount at one end of the laser tube while being outwardly spaced from the hollow mount. A power supply and modulator apply an alternating current to the induction coil.Type: GrantFiled: March 23, 1988Date of Patent: April 4, 1989Assignee: Aerotech, Inc.Inventors: Marc F. Aiello, John J. Grazulis
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Patent number: H882Abstract: Several gas-tight enclosures share a common optical cavity. The enclosures may be filled with neat gases or mixtures of gasses. The same gas or mixture, at the same or a different pressure, may occur in more than one enclosure. The gas or gasses in the various enclosures may be pulsed to lase in any desired sequence, simultaneously, or in any combination.Type: GrantFiled: June 1, 1989Date of Patent: January 1, 1991Inventor: Clifton S. Fox