Absorption Type Patents (Class 372/11)
  • Patent number: 7526004
    Abstract: A mode-locked laser apparatus includes a resonator (laser cavity), a mode-locking device placed in the resonator, a solid-stated laser medium that is doped with Yb (ytterbium) and placed in the resonator and an excitation means for causing excitation light to enter the solid-state laser medium. In the mode-locked laser apparatus, light with an oscillation wavelength in a wavelength band on the longer wavelength side of the maximum peak wavelength in a fluorescence spectrum of the solid-state laser medium is used as output light.
    Type: Grant
    Filed: October 4, 2006
    Date of Patent: April 28, 2009
    Assignee: FUJIFILM Corporation
    Inventors: Shogo Yamazoe, Takashi Adachi
  • Publication number: 20090080473
    Abstract: A semiconductor saturable absorber and the fabrication method thereof are provided. The semiconductor saturable absorber includes a Fe-doped InP substrate, a periodic unit comprising an AlGaInAs QW formed on the Fe-doped InP substrate and an InAlAs barrier layer formed on one side of the AlGaInAs QW, and another InAlAs barrier layer formed on the other side of the AlGaInAs QW. Each of the InAlAs barrier layers has a width being a half-wavelength of a light emitted by the AlGaInAs QW.
    Type: Application
    Filed: January 9, 2008
    Publication date: March 26, 2009
    Inventors: Kai-Feng HUANG, Yung-Fu Chen
  • Publication number: 20090016385
    Abstract: A laser apparatus 10 includes: a laser medium 11 arranged between a pair of reflecting means 12A and 12B of an optical resonator 12 and adapted to be excited to emit light; a saturable absorber 14 arranged on the optical axis L of the optical resonator 12 between the pair of reflecting means, the transmissivity thereof being adapted to increase with the absorption of emitted light 21 from the laser medium; and an excitation light source unit 13 adapted to output light 22 having a wavelength that excites the laser medium. The saturable absorber 14 is a crystalline body having first to third mutually perpendicular crystallographic axes and is arranged in the optical resonator 12 in such a manner as to have different transmissivities for emitted light in two mutually perpendicular polarization directions.
    Type: Application
    Filed: September 6, 2005
    Publication date: January 15, 2009
    Inventors: Hiroshi Sakai, Hirofumi Kan, Takunori Taira
  • Patent number: 7466727
    Abstract: A passive Q-switch for a laser system, and a method for its production. The laser is operative at near infrared wavelength region, including the eye-safe region. The Q-switch includes a saturable absorber based on IV-VI semiconductor nanocrystals (NCs), embedded in a polymer matrix. The NCs preferably include lead selenide, lead sulfide, or lead selenide sulfide. The NCs may be surface passivated, and may feature a PbSe/PbS core-shell configuration.
    Type: Grant
    Filed: October 16, 2006
    Date of Patent: December 16, 2008
    Assignees: ELOP Electro-Optics Industries Ltd., Technion Research and Development Foundation Ltd.
    Inventors: Ehud Galun, Efrat Lifshitz, Marina Sirota, Vladimir Krupkin, Aldona Sashchiuk
  • Patent number: 7463660
    Abstract: A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. By roughening one or more peripheral edges of a solid-state crystal or ceramic laser gain media and by bonding such edges using a substantially high index bonding elastomer or epoxy to a predetermined electromagnetic absorbing arranged adjacent to the entire outer surface of the peripheral edges of the roughened laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.
    Type: Grant
    Filed: November 8, 2004
    Date of Patent: December 9, 2008
    Assignee: Lawrence Livermore National Laboratory, LLC
    Inventors: Lloyd A. Hackel, Thomas F. Soules, Scott N. Fochs, Mark D. Rotter, Stephan A. Letts
  • Patent number: 7397828
    Abstract: A laser system comprises a reflective chamber capable of housing a laser medium and at least two laser diodes emitting light at different respective wavelengths into the reflective chamber. The wavelength of each respective laser diode may be selected to minimize fluctuations in absorption by the laser medium of light emitted by the diode bars as the wavelength of each respective laser diode changes due to changes in an operating temperature of the laser system. The wavelength of each respective laser diode may be selected such that absorption by the laser medium of the wavelength of light emitted by one laser diode increases and absorption by the laser medium of the wavelength of light emitted by another laser diode decreases as the operating temperature changes within a predefined range.
    Type: Grant
    Filed: June 28, 2005
    Date of Patent: July 8, 2008
    Assignee: Northrop Grumman Corporation
    Inventors: Christopher M. DePriest, Mark A. Decker, Matthew D. Hawk, Steven J. Lindauer, Laurance S. Lingvay, Gary D. Ross, Douglas P. Stanley
  • Publication number: 20080151946
    Abstract: There is provided a solid-state laser apparatus, including a solid-state active element (4) having major surfaces and first and second edges (10,12) oppositely disposed to each other, the first edge (10) being flat and the second edge (12) being constituted by first and second perpendicularly disposed surfaces (12) or having first and second perpendicularly disposed surfaces (12) located adjacent to the second edge, a back reflector (16) and an output coupler (18) located at, or adjacent to, the first edge (10). Light induced in the cavity forms two parallel beams passing therethrough, by means of a first beam which is reflected by the back reflector (16) towards a first of the perpendicularly disposed surfaces and being folded to pass on to the second surface, to be further folded and to proceed towards the first edge (10). A saturable absorber (14) may be attached to the first edge (10).
    Type: Application
    Filed: February 27, 2006
    Publication date: June 26, 2008
    Applicant: ELBIT SYSTEMS ELECTRO-OPTICS ELOP LTD.
    Inventors: Nissim Zafrani, Yuval Artstein
  • Patent number: 7391794
    Abstract: A non-linearly frequency-converted Q-switched laser is “injection seeded” with short pulses from another laser, called a seed laser. Radiation produced by the Q-switched laser is frequency converted in a non-linear process. The injection seeding can enhance peak power and frequency conversion efficiency while reducing damage to a non-linear medium used to frequency convert radiation generated by the Q-switched laser.
    Type: Grant
    Filed: May 25, 2005
    Date of Patent: June 24, 2008
    Assignee: JDS Uniphase Corporation
    Inventor: Thomas J. Kane
  • Patent number: 7376354
    Abstract: All optical clock recovery includes a transmitter for generating an optical timing signal. The transmitter includes a semiconductor laser for the production of a dynamically synchronizable timing signal, the laser having an external resonator for feedback of the timing signal to the laser, the feedback having a delay time greater than a relaxation oscillation time for the laser, and the laser outputting an optical timing signal having a characteristic dynamic. The transmitter supplies the optical timing signal to a receiver configured to receive the timing signal and to synchronize to the laser on receipt of the timing signal, such that the receiver outputs a recovered timing signal having the characteristic dynamic.
    Type: Grant
    Filed: August 1, 2006
    Date of Patent: May 20, 2008
    Assignee: Nortel Networks Limited
    Inventor: John Kenton White
  • Patent number: 7356053
    Abstract: A pulsed, mode-locked, picosecond laser having a solid-state laser medium, a saturable absorber (SA), and a passive negative feedback (PNF) element. The SA is “slow,” having an absorption recovery time which is longer than a desired duration of an output pulse. The SA and the PNF element together mode-lock the laser to produce an output pulse or pulses of a given duration. The position of the SA along the beam path and the orientation of the SA with respect to the beam path can be varied to vary the output pulse duration over a wide range.
    Type: Grant
    Filed: October 6, 2003
    Date of Patent: April 8, 2008
    Assignee: Continuum Electro-Optics, Inc.
    Inventor: Dzhakhangir V. Khaydarov
  • Patent number: 7324568
    Abstract: A modulated saturable absorber controlled laser. The laser includes an active medium; a saturable absorber material operationally coupled to the medium to serve as a passive Q switch; and an energy source disposed external to the medium for apply energy to the absorber. In particular embodiments, the energy source is a diode laser and focusing optics are included between the diode laser and the absorber. Modulation of the gain at the photon round trip time in the laser resonator causes a mode-locked laser output. A dichroic beamsplitter is included in this embodiment for directing energy to the absorber. In an alternative embodiment, the diode laser is a quasi-monolithic diode laser assembly ring.
    Type: Grant
    Filed: April 8, 2004
    Date of Patent: January 29, 2008
    Assignee: Raytheon Company
    Inventors: Kalin Spariosu, Milton Birnbaum
  • Patent number: 7319708
    Abstract: A passive Q-switch element is disclosed that permits operating a laser with a variable pulse repetition frequency (PRF). The Q-switch comprises two wedges of material, one made from saturable absorber material, the other from transparent material, with the two wedges mounted together to form a constant optical thickness block. By translating the block transversely to a laser beam the amount of saturable absorber material seen by the laser beam is altered and as a result the PRF of the laser is varied.
    Type: Grant
    Filed: February 22, 2005
    Date of Patent: January 15, 2008
    Assignee: Lockheed Martin Coherent Technologies, Inc.
    Inventors: John E. Koroshetz, Josef R. Unternahrer
  • Publication number: 20070280324
    Abstract: The laser apparatus for generating high energy pulses of short duration comprises a pumping laser source and a miniaturized cavity defined by a pair of mirrors in which an active crystal and an absorber are housed. The active crystal presents a gain greater than 10 dB in double pass, said absorber being a saturable absorber. The process for generating a laser pulse consists of generating a beam of modes within a cavity and amplifying only one of the modes, so that the resultant signal presents a very limited duration but a very high intensity, with a spatial quality close to the diffraction limit.
    Type: Application
    Filed: May 31, 2007
    Publication date: December 6, 2007
    Inventor: Giuliano Piccinno
  • Patent number: 7203209
    Abstract: The laser includes a resonant cavity formed between a first mirror and a second mirror. An unsensitized Erbium-doped crystal gain medium for producing laser gain is disposed within the resonant cavity. A saturable absorber is disposed within the resonant cavity. A pump source is positioned to energize the gain medium. The saturable absorber, the laser gain, the resonator length, and the second mirror being selected so that output pulses having a duration of less than 75 nanoseconds are generated by the laser.
    Type: Grant
    Filed: January 19, 2005
    Date of Patent: April 10, 2007
    Assignee: BAE Systems Information and Electronic Systems Integration Inc.
    Inventors: York E. Young, Scott D. Setzler
  • Patent number: 7149231
    Abstract: A monolithic, side pumped, passively Q-switched, solid-state laser (10) includes a laser resonator structure (16) that includes a laser gain medium (12) having an output face bonded to a passive Q-switch (14). The gain medium (12) has a side face (12A) for receiving pump light. The pump light is preferably generated by a laser diode array (20). In a further embodiment, a non-linear optical material (22), such as frequency doubling KTP, is optically coupled to an output face of the Q-switch for providing output wavelength conversion. A method is also disclosed for fabricating the monolithic, side pumped, passively Q-switched, solid-state laser. Techniques are included for providing compensation from thermal aberrations during operation of the laser.
    Type: Grant
    Filed: October 3, 2003
    Date of Patent: December 12, 2006
    Assignee: Spectra Systems Corporation
    Inventors: Robert S. Afzal, Andrei Smuk
  • Patent number: 7103282
    Abstract: All optical clock recovery includes a transmitter for generating an optical timing signal. The transmitter includes a semiconductor laser for the production of a dynamically synchronizable timing signal, the laser having an external resonator for feedback of the timing signal to the laser, the feedback having a delay time greater than a relaxation oscillation time for the laser, and the laser outputting an optical timing signal having a characteristic dynamic. The transmitter supplies the optical timing signal to a receiver configured to receive the timing signal and to synchronize to the laser on receipt of the timing signal, such that the receiver outputs a recovered timing signal having the characteristic dynamic.
    Type: Grant
    Filed: July 10, 2002
    Date of Patent: September 5, 2006
    Assignee: Nortel Networks Limited
    Inventor: John Kenton White
  • Patent number: 7087447
    Abstract: A method for batch manufacturing of slabs for zig-zag lasers including steps of bonding two non-active media to either side of an active medium to form a sandwich, dicing the sandwich to provide slices, rendering two surfaces of each slice into total-internal-reflection (TIR) surfaces, and then dicing the slices perpendicular to the TIR surfaces to provide a plurality of zig-zag slabs.
    Type: Grant
    Filed: October 28, 2003
    Date of Patent: August 8, 2006
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Arun Kumar Sridharan, Shailendhar Saraf, Robert L. Byer
  • Patent number: 7065121
    Abstract: Methods and systems for laser-based processing of materials are disclosed wherein a scalable laser architecture, based on planar waveguide technology, provides for pulsed laser micromachining applications while supporting higher average power applications like laser welding and cutting. Various embodiments relate to improvements in planar waveguide technology which provide for stable operation at high powers with a reduction in spurious outputs and thermal effects. At least one embodiment provides for micromachining with pulsewidths in the range of femtoseconds to nanoseconds. In another embodiment, 100 W or greater average output power operation is provided for with a diode-pumped, planar waveguide architecture.
    Type: Grant
    Filed: November 13, 2002
    Date of Patent: June 20, 2006
    Assignee: GSI Group Ltd.
    Inventors: David M. Filgas, Frank Haran, Andreas Mank, John Robertson
  • Patent number: 7027479
    Abstract: A volume-absorbing laser beam dump encloses a solution comprising a laser-absorbing solute diluted in a solvent that is non-absorbent of the laser energy. The laser beam dump includes a window to admit a laser beam into the solution. As the laser beam travels through the solution, the diluted solute absorbs the laser energy.
    Type: Grant
    Filed: December 3, 2003
    Date of Patent: April 11, 2006
    Assignee: The Boeing Company
    Inventors: Alan F. Stewart, Rashmi S. Shah, Gregory M. Yagiela
  • Patent number: 7027471
    Abstract: The invention relates to a laser system using a multi-longitudinal-mode Fabry-Perot laser diode as an inter-injection light source and a gain cavity formed by other laser diodes of such type so as to achieve the function of fast wavelength switching, so that it is possible to achieve repetitively fast switching of wavelength by varying and controlling the bias voltage of maximum optical gain in said inter-injection type multi-longitudinal-mode Fabry-Perot laser diode so as to achieve three different wavelengths with tuning range of 3.5 nm for a side-mode suppression ratio (SMSR) greater than 19 dB and a response time of wavelength switching in the order of nanosecond.
    Type: Grant
    Filed: April 23, 2004
    Date of Patent: April 11, 2006
    Assignee: National Chiao Tung University
    Inventors: Sien Chi, Chien-Chung Lee, Chien-Hung Yeh
  • Patent number: 6990127
    Abstract: A vertical laser diode includes a vertical resonator and a device for shaping the beam profile of the laser diode. The shaping device has at least one decoloring absorber. The configuration provide a vertical laser diode structure that permits stable beam profile shaping.
    Type: Grant
    Filed: January 15, 2002
    Date of Patent: January 24, 2006
    Assignee: Infineon Technologies AG
    Inventors: Karl Joachim Ebeling, Thomas Knödl
  • Patent number: 6973115
    Abstract: This invention relates to a laser cavity with passive triggering by saturable absorbent and with controlled polarization, and to a laser and in particular to a microlaser containing the said cavity and means of pumping this cavity. The invention also relates to a process for manufacturing the said microlaser. The laser cavity with controlled polarization comprises a substrate made of Y3Al5O12 (YAG) active laser material that may or may not be doped, on which a monocrystalline layer of saturable absorbent doped YAG material is deposited directly by liquid phase epitaxy or by a similar process, in which the said active laser material has a [100] orientation, and in which the said monocrystalline layer of saturable absorbent material is deposited with the same [100] orientation.
    Type: Grant
    Filed: December 23, 1998
    Date of Patent: December 6, 2005
    Assignee: Commissariat a l'Energie Atomique
    Inventors: Bernard Ferrand, Bernard Chambaz, Laurent Fulbert, Jean Marty
  • Patent number: 6956887
    Abstract: An intracavity resonant Fabry-Perot saturable absorber (R-FPSA) induces modelocking in a laser such as a fiber laser. An optical limiter such as a two photon absorber (TPA) can be used in conjunction with the R-FPSA, so that Q-switching is inhibited, resulting in laser output that is cw modelocked. By using both an R-FPSA and a TPA, the Q-switched modelocked behavior of a fiber laser is observed to evolve into cw modelocking.
    Type: Grant
    Filed: December 15, 2000
    Date of Patent: October 18, 2005
    Assignee: Imra America, Inc.
    Inventors: Min Jiang, Donald J. Harter, Gregg D. Sucha, Martin E. Fermann
  • Patent number: 6944201
    Abstract: The solid state laser comprises a laser gain medium (1), pumping means for pumping the laser gain medium, and a laser cavity having a first end (3) and a second end (17), wherein the laser gain medium is at, or in the vicinity of, said first end (3) of said cavity. A semiconductor saturable absorber mirror (SESAM) can be placed at the second end (17) of the cavity. The laser gain medium can comprise at least one face for receiving pumping energy from the pumping means, the face being made reflective at a laser frequency of the laser, so that it can form the first end of the laser cavity. The resulting setup used for generating femtosecond laser pulses.
    Type: Grant
    Filed: January 24, 2002
    Date of Patent: September 13, 2005
    Assignee: High Q Laser Production GmbH
    Inventors: Udo Bunting, Daniel Kopf
  • Patent number: 6931047
    Abstract: In the first period from pumping start time T1 to time T2 in a laser light source 1, the power of pumping light L1 outputted from a pumping light source 41 so as to irradiate a laser medium 21 is at value P1 whereas the power of light L2 incident on a saturable absorber 30 after being emitted from the laser medium 21 is at an absorption saturation threshold or lower, which causes a resonator 10 to lower its Q-value, thereby suppressing the laser oscillation. Immediately before time T2, the power of light L2 is slightly lower than the absorption saturation threshold. In the second period subsequent to the first period, the power of light L2 is at value P2 greater than the above-mentioned value P1, whereas the power of light L2 exceeds the absorption saturation threshold, which causes the resonator 10 to increase its Q-value, whereby a mirror 12 outputs pulse laser light L3 to the outside.
    Type: Grant
    Filed: December 24, 2002
    Date of Patent: August 16, 2005
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Hirofumi Kan, Akihiro Sone, Hiroshi Sakai, Takunori Taira, Nicolaie Pavel, Voicu Lupei
  • Patent number: 6920082
    Abstract: The present invention is a method of determining formation horizontal shear wave velocity, formation transverse isotropy and an effective logging tool modulus. The method comprises determining an effective logging tool modulus by modeling the logging tool as a fluid filled cylindrical shell. Measured Stoneley-wave slowness values are acquired for a formation. A horizontal formation shear wave velocity, Vsh, is calculated as a function of the measured Stoneley-wave slowness and an estimated Stoneley-wave slowness wherein the estimated average Stoneley-wave slowness is computed using the effective tool modulus. A difference between the measured Stoneley-wave slowness and the estimated Stoneley-wave slowness is minimized and the horizontal shear-wave velocity value for the minimized difference is output. Transverse isotropy may be then be calculated as a function of the determined Vsh and vertical shear wave velocity, Vsv, determined from standard logging techniques.
    Type: Grant
    Filed: June 27, 2002
    Date of Patent: July 19, 2005
    Assignee: Baker Hughes Incorporated
    Inventor: Xiao Ming Tang
  • Patent number: 6856631
    Abstract: A self-pulsating semiconductor laser device includes a semiconductor substrate of the first conductivity type, a first cladding layer of the first conductivity type formed on the substrate and an active layer formed on the first cladding layer. A second cladding layer of a second conductivity type is formed on the active layer. A saturable absorbing layer is formed on at least portions of at least one of the first cladding layer and the second cladding layer. The saturable absorbing layer has a band gap energy either approximately the same as, or slightly smaller than, the active layer.
    Type: Grant
    Filed: September 29, 1999
    Date of Patent: February 15, 2005
    Assignee: Ricoh Company, Ltd.
    Inventor: Takashi Takahashi
  • Patent number: 6842466
    Abstract: A semiconductor wafer with variable transmittance, serves as a saturable absorber for performing passive Q-switching in a laser system to produce laser pulses having defined output characteristics. By translating or rotating the semiconductor saturable absorber, loss properties of a laser cavity may be altered. In this manner, the output characteristics of the laser pulses can be varied without changing other parameters of laser operation. The output characteristics may include pulse duration, pulse repetition rate, peak power and average output power of the laser pulses. The semiconductor wafer can be made of doped or undoped GaAs, AlGaAs, InP, etc. Furthermore, the tunable Q-switch may simultaneously serve as an output coupler for the laser cavity.
    Type: Grant
    Filed: July 18, 2000
    Date of Patent: January 11, 2005
    Assignee: Nanyang Technological University
    Inventors: Siu Chung Tam, Jian Hui Gu, Yee Loy Lam
  • Patent number: 6839362
    Abstract: A saturable absorber Q-switch includes a monocrystalline lattice having the formula Mg1-xCoxAlyOz where x is greater than 0 and less than 1, y is greater than 2 and less than about 8, and z is between about 4 and 13. The lattice has tetrahedral and octahedral positions, and most of the magnesium and cobalt occupy tetrahedral positions. In one embodiment, the molar ratio of aluminum to the combined amount of magnesium and cobalt in the monocrystalline lattice can be controlled during growth of the monocrystalline lattice to thereby form a saturable absorber Q-switch that exhibits a 4T1 spectrum for the cobalt ion of at least about 1544 ?m.
    Type: Grant
    Filed: May 22, 2001
    Date of Patent: January 4, 2005
    Assignee: Saint-Gobain Ceramics & Plastics, Inc.
    Inventors: Milan R. Kokta, Dennis L. Peressini, Jeffrey A. Cooke, Kevin L. Goodnight
  • Patent number: 6834064
    Abstract: A pulsed solid-state thin-disk laser comprises an optical resonator and a solid-state laser gain medium placed inside the optical resonator. The laser gain medium is in the shape of a thin plate or layer with two end faces, the extension of the end faces being greater than a thickness of said plate or layer measured in a direction perpendicular to one of the end faces. One of the end faces comprises a cooling surface, via which the laser gain medium is cooled. A pumping source is provided for exciting the laser gain medium to emit electromagnetic radiation. The thin-disk laser further comprises means for passive mode locking placed inside the optical resonator. The mode-locking means are preferably a semiconductor saturable absorber mirror (SESAM). The laser offers a high average power, a good beam quality, short pulses and a high efficiency. Problems such as thermal lensing, Q-switching instabilities and damages of the mode-locking means are avoided. Moreover, the output power of the laser is scalable, i.e.
    Type: Grant
    Filed: March 17, 2000
    Date of Patent: December 21, 2004
    Assignee: Time-Bandwidth Products AG
    Inventors: Ruediger Paschotta, Juerg Aus Der Au, Gabriel J Spuehler, Ursula Keller
  • Patent number: 6826205
    Abstract: A Saturable Reflector apparatus comprises a substrate having a first and second surfaces, and a reflector having a saturable absorber layer, attached to the first surface. At least one of the first and second surfaces has been modified to enhance an etalon effect of the substrate due to interference of light reflecting from the first and second surfaces. Either or both of the surfaces may be modified, for example, by polishing or coating. The apparatus may also include means for adjusting an optical thickness of the substrate to tune the etalon effect. Such means may comprise a temperature control element, such as a heater, coupled to a temperature controller. The inventive apparatus may be incorporated into a mode-locked laser. The etalon tuning optimizes a relation between temporal and frequency domains of radiation incident on the saturable reflector.
    Type: Grant
    Filed: May 22, 2000
    Date of Patent: November 30, 2004
    Assignee: Lightwave Electronics Corporation
    Inventors: Lawrence E. Myers, Jason I. Alexander
  • Publication number: 20040223523
    Abstract: A CPT detector and a method for detecting CPT are disclosed. The CPT detector includes a quantum absorber, a polarization analyzer, and a detector. The quantum absorber includes a material having first and second low energy states coupled to a common high energy state. Transitions between the first low energy state and the common high energy state and between the second low energy state and the common high energy state are induced by electromagnetic radiation having a predetermined polarization state. The polarization analyzer blocks electromagnetic radiation of the predetermined polarization while passing electromagnetic radiation having a polarization state that is orthogonal to the predetermined polarization. The polarization analyzer is irradiated with a portion of the generated electromagnetic radiation that has passed through the quantum absorber. The detector generates a signal related to the intensity of electromagnetic radiation that leaves the polarization analyzer.
    Type: Application
    Filed: April 28, 2003
    Publication date: November 11, 2004
    Inventor: Miao Zhu
  • Patent number: 6813285
    Abstract: A Q-switched microlaser is provided that is capable of supporting a zig-zag resonation pattern in response to pumping of the active gain medium so as to effectively lengthen the microresonator cavity without having to physically lengthen the microresonator cavity. As such, the microlaser can generate pulses having greater pulse widths and correspondingly greater pulse energies and average power levels than the pulses provided by conventional microlasers of a similar size. A corresponding fabrication method is also provided that permits a plurality of Q-switched microlasers to be fabricated in an efficient and repeatable manner.
    Type: Grant
    Filed: September 4, 2002
    Date of Patent: November 2, 2004
    Assignee: LItton Systems, Inc.
    Inventor: Brian Lee Peterson
  • Patent number: 6804282
    Abstract: A multilayer film includes alternately laminated, a first film with a refractive index of n1 and a second film with a refractive index of n2, the multilayer film having the first film in contact with an end face of a semiconductor laser element. The first film and the second film satisfy relations expressed by the formulas n1<(nc)1/2 and n2>(nc)1/2. The reflectivity characteristic of the multilayer film has a 1 maximum at a wavelength &lgr;1 in a wavelength region and minimums at wavelengths &lgr;2 and &lgr;3 on a shorter-wavelength side and a longer-wavelength side of the wavelength &lgr;1, respectively.
    Type: Grant
    Filed: February 6, 2003
    Date of Patent: October 12, 2004
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kimio Shigihara, Kazushige Kawasaki
  • Patent number: 6795475
    Abstract: A semiconductor-laser-excited solid-state laser apparatus includes a solid-state laser element and a semiconductor laser unit including a resonator. The solid-state laser element is excited by light emitted from the semiconductor laser unit, and emits laser light. The resonator length in the semiconductor laser unit is arranged to be at least 0.8 mm, so as to reduce an amount of wavelength shift in light emitted from the semiconductor laser unit, and achieve a stable, high-power laser output from the semiconductor-laser-excited solid-state laser apparatus.
    Type: Grant
    Filed: April 19, 2000
    Date of Patent: September 21, 2004
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Hisashi Ohtsuka, Yoji Okazaki
  • Patent number: 6788715
    Abstract: An IAU laser is stabilized to reduce intensity fluctuations. The laser comprises an IAU gain medium disposed in an optical resonance cavity and a multiphoton absorbing medium disposed in the cavity to reduce intensity fluctuations. A pump source to excite the gain medium is coupled to the cavity. In operation, the multiphoton absorbing material absorbs primarily at high intensity levels, effectively increasing the loss at high intensities. In an advantageous embodiment, the active medium comprises erbium-doped glass and the multiphoton absorber comprises a body of semiconductor exhibiting two-photon absorption at the emission wavelength.
    Type: Grant
    Filed: May 30, 2003
    Date of Patent: September 7, 2004
    Assignee: Princeton Optronics
    Inventors: Robert Van Leeuwen, Thomas Oh
  • Patent number: 6788713
    Abstract: Output power fluctuations in a distributed feedback laser arrangement are reduced by inducing a saturable absorption grating in a saturable absorption region. Light is coupled into a DFB region and amplified in an amplification region. A feedback loop reflects a portion of the amplified light, and the counter-propagating beams induce an absorption grating in a saturable absorption region which suppresses output oscillations. The amplification region can comprise an erbium doped fiber, and the saturable absorption region can comprise an underpumped portion of such a fiber, or a further length of such fiber, or a planar waveguide.
    Type: Grant
    Filed: May 16, 2001
    Date of Patent: September 7, 2004
    Assignee: The University of Sydney
    Inventors: Dmitrii Stepanov, Zourab Brodzeli
  • Patent number: 6778563
    Abstract: A microchip laser arrangement is disclosed. The arrangement is operative to emit Q-switched laser pulses at 1.54 &mgr;m. The lasing medium of the laser arrangement is preferably comprised of Yb:Er-glass, and the Q-switch is comprised of a saturable absorber of cobalt doped spinel crystal. The lasing medium is preferably bonded to the absorber to form a monolithic body, upon the surface of which there are deposited dielectric stacks forming a resonant laser cavity. Pumping of the active medium is performed by means of an InGaAs laser diode emitting light at 0.97 &mgr;m, corresponding well with the absorption of the Yb:Er-glass material.
    Type: Grant
    Filed: June 5, 2001
    Date of Patent: August 17, 2004
    Assignee: Cobolt AB
    Inventors: Fredrik Laurell, Valdas Pasiskevicius, Boris Ivanovic Galagan, Gunnar Karlsson, Boris Ilich Denker, Sergei Evgenievich Sverchkov
  • Patent number: 6778565
    Abstract: An optically pumped laser with an Er:Yb: doped solid state gain element is disclosed, which is passively mode-locked by means of a saturable absorber mirror. The laser is designed to operate at a fundamental repetition rate exceeding 1 GHz and preferably at an effective wavelength between 1525 nm and 1570 nm. Compared to state of the art solid state pulsed lasers, the threshold for Q-switched-mode-locked operation is substantially improved. Thus, according to one embodiment, the laser achieves a repetition rate beyond 40 GHz. The laser preferably comprises means for wavelength tuning and repetition rate locking.
    Type: Grant
    Filed: November 5, 2002
    Date of Patent: August 17, 2004
    Assignee: Gigatera AG
    Inventors: Gabriel J. Spuehler, Lukas Krainer, Kurt Weingarten, Rudiger Paschotta, Ursula Keller
  • Patent number: 6741619
    Abstract: Systems and methods for enhancing the stability of a mode-locked laser's output are disclosed. The laser systems include a mode-locking element that mode-locks the laser's output, and a semiconductor element. The semiconductor element produces a loss at the laser's operative wavelength that increases as pulse energy increases, thereby enhancing the stability of the mode-locked output. The semiconductor elements can be used to enhance stability of both passively and actively mode-locked laser systems.
    Type: Grant
    Filed: April 3, 2000
    Date of Patent: May 25, 2004
    Assignee: Massachusetts Institute of Technology
    Inventors: Erik R. Thoen, Elisabeth M. Koontz, Erich P. Ippen, Leslie A. Kolodziejski, Franz X. Kaertner, Hermann A. Haus, Matthew E. Grein
  • Patent number: 6738399
    Abstract: The present invention provides an edge cladding for a slab laser, the edge cladding comprising a cooling channel system therein.
    Type: Grant
    Filed: May 17, 2001
    Date of Patent: May 18, 2004
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Georg F. Albrecht, Raymond J. Beach, Richard W. Solarz
  • Patent number: 6738408
    Abstract: A mode-locked laser apparatus includes a mode-locked laser oscillator, a detection device for detecting changes in the optical path length of the mode-locked laser oscillator by utilizing the chromatic dispersion characteristics of the optical path, an optical path length controller that controls the optical path length of the laser oscillator, and a feedback circuit that controls the optical path length controller by means of the signal detected by the detection device.
    Type: Grant
    Filed: March 15, 2001
    Date of Patent: May 18, 2004
    Assignee: Communications Research Laboratory, Independent Administrative Institution
    Inventor: Kazi Sarwar Abedin
  • Patent number: 6665111
    Abstract: An array of devices for electronically steering a laser beam. A plurality of quantum well absorption modulators steer a laser beam, either reflective or transmissive, without moving parts and operable at room temperature. The foregoing is accomplished using intraband, also termed intersubband, transitions in the quantum wells.
    Type: Grant
    Filed: May 13, 2002
    Date of Patent: December 16, 2003
    Assignee: Teraconnect, Inc.
    Inventor: Mani Sundaram
  • Publication number: 20030179786
    Abstract: The combination of coupling, modes and a Q-switch allows amplitude modulated laser pulses to be produced which contain a high output capability and high repetitive rate. The envelope of the pulse of the coupling modes in the shape of a Q-switch-pulse varies in intensity. Preferably, said combination is achieved by using, a satiated semiconductor absorber (SESAM), whereby the parameters thereof must be specially adjusted to the other elements used, so that the requirement for high repetitive Q-switch-pulse rates can be met.
    Type: Application
    Filed: May 29, 2003
    Publication date: September 25, 2003
    Inventor: Daniel Kopf
  • Patent number: 6625192
    Abstract: An optical pulse generator, consisting of a semiconductor device and an optical output assembly. The semiconductor device includes an optically-active region having a gain section and a saturable absorber (SA) section, which are adapted to generate coherent optical pulses. The device also includes an output facet for coupling therethrough of the optical pulses generated in the optically-active region, and an SA electrode for application of a radio-frequency (RF) modulation of a desired frequency to the SA section. The optical output assembly is optically coupled to the output facet of the semiconductor device so as to partially reflect the coherent optical pulses within a predetermined wavelength range.
    Type: Grant
    Filed: January 22, 2001
    Date of Patent: September 23, 2003
    Assignee: Cyoptics (Israel) Ltd.
    Inventors: David Arbel, Uzi Koren, Micha Zimmermann
  • Patent number: 6574250
    Abstract: A burst (50) of ultrashort laser pulses (52) is employed to sever a conductive link (22) in a nonthermal manner and offers a wider processing window, eliminates undesirable HAZ effects, and achieves superior severed link quality. The duration of the burst (50) is preferably in the range of 10 ns to 500 ns; and the pulse width of each laser pulse (52) within the burst (50) is generally shorter than 25 ps, preferably shorter than or equal to 10 ps, and most preferably about 10 ps to 100 fs or shorter. The burst (50) can be treated as a single “pulse” by conventional laser positioning systems (62) to perform on-the-fly link removal without stopping whenever the laser system (60) fires a burst (50) of laser pulses (52) at each link (22). Conventional wavelengths or their harmonics can be employed.
    Type: Grant
    Filed: January 9, 2001
    Date of Patent: June 3, 2003
    Assignee: Electro Scientific Industries, Inc.
    Inventors: Yunlong Sun, Edward J. Swenson, Richard S. Harris
  • Patent number: 6560268
    Abstract: A resonator mirror with a saturable absorber for a laser wavelength &lgr;L formed of a series of layers of a plurality of semiconductor layers on a substrate, wherein a Bragg reflector formed of a plurality of alternately arranged layers comprising a first material with an index of refraction nH and a second material with a lower index of refraction NL compared with the latter is grown on a surface of the substrate. It is characterized in that a threefold layer is grown on the Bragg reflector, wherein a single quantum layer is embedded within two layers outside an intensity minimum for the laser radiation &lgr;L and the threefold layer has a combined optical thickness of λ L 2 .
    Type: Grant
    Filed: July 24, 2000
    Date of Patent: May 6, 2003
    Assignee: LDT GmbH & Co. Laser-Display-Technologie KG
    Inventors: Eckard Deichsel, Roland Jaeger, Peter Unger
  • Publication number: 20030007520
    Abstract: A saturable absorber Q-switch includes a monocrystalline lattice having the formula Mg1-xCoxAlyOz where x is greater than 0 and less than 1, y is greater than 2 and less than about 8, and z is between about 4 and 13. The lattice has tetrahedral and octahedral positions, and most of the magnesium and cobalt occupy tetrahedral positions. In one embodiment, the molar ratio of aluminum to the combined amount of magnesium and cobalt in the monocrystalline lattice can be controlled during growth of the monocrystalline lattice to thereby form a saturable absorber Q-switch that exhibits a 4T1 spectrum for the cobalt ion of at least about 1544 &mgr;m.
    Type: Application
    Filed: May 22, 2001
    Publication date: January 9, 2003
    Applicant: Saint-Gobain Ceramics & Plastics, Inc.
    Inventors: Milan R. Kokta, Dennis L. Peressini, Jeffrey A. Cooke, Kevin L. Goodnight
  • Publication number: 20020181513
    Abstract: A microchip laser arrangement is disclosed. The arrangement is operative to emit Q-switched laser pulses at 1.54 &mgr;m. The lasing medium of the laser arrangement is preferably comprised of Yb:Er-glass, and the Q-switch is comprised of a saturable absorber of cobalt doped spinel crystal. The lasing medium is preferably bonded to the absorber to form a monolithic body, upon the surface of which there are deposited dielectric stacks forming a resonant laser cavity, Pumping of the active medium is performed by means of an InGaAs laser diode emitting light at 0.97 &mgr;m, corresponding well with the absorption of the Yb:Er-glass material.
    Type: Application
    Filed: June 5, 2001
    Publication date: December 5, 2002
    Inventors: Fredrik Laurell, Valdas Pasiskevicius, Boris Ivanovic Galagan, Gunnar Karlsson, Boris Ilich Denker, Sergei Evgenievich Sverchkov
  • Patent number: RE38489
    Abstract: The invention relates to a microlaser cavity (10) having: a solid active medium (2) emitting at least in a wavelength range between 1.5 and 1.6 &mgr;m, and a saturable absorber (4) of formula CaF2:Co2+ or MgF2:Co2+ or SrF2:Co2+ or BaF2:Co2+ or La0.9Mg0.5-xCoxAl11.433O19 or YalO3:Co2+ (or YAl5-2xCoxSixO3 YAl(1-2x)CoxSixO3) or Y3Al5-x-yGaxScyO12:Co2+ (or -3Al5-x-y2zGaxScyCozSizO12 Y3Al5-x-y-2zGaxScyCozSizO12) or Y3-xLuxAl5O12:Co2+ (or Y3-xLuxAl5-2yCoySiyO3) or Sr1-xMgxLayAl12-yO12:Co2+ (or Sr1-xMgx-yCoyLazAl12-zO12, with 0<y<x) Sr1-xLaxMgxAl12-xO19:Co2+ (or Sr1-xLaxMgx-yCoyAl12-xO19 , with 0<y<x).
    Type: Grant
    Filed: February 8, 2002
    Date of Patent: April 6, 2004
    Assignee: Commissariat a l'Energie Atomique
    Inventors: Philippe Thony, Engin Molva, Bernard Ferrand, Corinne Borel