Abstract: In a first embodiment, the invention makes use of a Neodymium doped YAG (Nd:YAG) gain medium placed in an optical resonant cavity formed by two mirrors. Power extraction is maximized for a specific laser cavity. In particular the concave curvature on the rod ends contributes a negative lensing component to modify the strength of the thermal lens. In a second embodiment the present invention uses an amplifier rod medium with curved ends to act as lensing elements to collect emission from the laser gain medium and/or oscillator described in the first embodiment of the invention. The combination of thermal lens and curved rod ends produces a lensing effect which allows light to be directly coupled from a laser. In addition, variation of the input pump power allows for control of the thermal lens formed within the amplifier rod.

Abstract: A system and method for optical frequency conversion having asymmetric output include a coherent light apparatus. The coherent light apparatus includes a coherent light source that produces a first coherent light, a frequency converter optically coupled to the coherent light source, and a coupling optic optically coupled between the coherent light source and the frequency converter. The frequency converter converts the first coherent light to a second coherent light at a second frequency and includes an asymmetric frequency converter (AFC) that nonlinearly converts the first coherent light to the second coherent light with the frequency conversion being more efficient in a first direction than in a second direction. A resonant cavity formed about the AFC circulates the first coherent light and transmits the second coherent light propagating in the first direction.

Abstract: A surface emitting semiconductor laser includes a semiconductor chip (1), which emits radiation (12) and contains a first resonator mirror (3). A second resonator mirror (6) is arranged outside the semiconductor chip (1). The first resonator mirror (3) and the second resonator mirror (6) form a laser resonator for the radiation (12) emitted by the semiconductor chip (1). The laser resonator contains an interference filter (9, 17), which is formed from an interference layer system comprising a plurality of dielectric layers.

Abstract: A mode-locked laser device includes a Fabry-Perot resonator, a mode-locking element disposed within the resonator, a solid-state laser medium disposed within the resonator, and exciting means for applying excitation light to the solid-state laser medium. The opposite ends of the resonator, the mode-locking element and the solid-state laser medium are disposed to provide an average beam diameter of lasing light of not more than 150 ?m on the mode-locking element and an average beam diameter of the lasing light of not more than 200 ?m within the solid-state laser medium.

Abstract: An optically pumped semiconductor-laser (OPS-laser) resonator includes an arrangement for delivering optical pump radiation on an OPS-chip to cause fundamental radiation to circulate in the resonator. The resonator includes second and third-harmonic generating crystals and is arranged deliver third-harmonic radiation. The resonator also includes a stop positioned and configured to stabilize the laser output. The pump radiation arrangement delivers the pump radiation at an angle to the resonator axis and includes wedged GRIN lens arranged such that the pump radiation forms a circular spot on the OPS chip. The third harmonic generating crystal acts as a polarizer for the fundamental radiation and angularly separates fundamental and third harmonic beams.

Abstract: In accordance with the present invention, a compact laser system with nearly continuous wavelength scanning is presented. In some embodiments, the compact laser system can be scanned over a broad range. In some embodiments, the compact laser system can be scanned at high scan rates. In some embodiments, the compact laser system can have a variable coherence length. In particular, embodiments with wavelength scanning over 140 nm with continuously variable scan rates of up to about 1 nm/?s, and discrete increase in scan rates up to about 10 nm/?s, and variable coherence lengths of from 1 mm to about 30 mm can be achieved.

Abstract: Photonic crystal cavities and related devices and methods are described. The described cavities can be used as lasers, photovoltaic sources, and single photon sources. The cavities can be both optically and electrically pumped. A fabrication process of the cavities is also described.

Abstract: A semiconductor laser excitation solid laser control device 1A according to the present invention is a control device for stabilizing a light quantity of an output light LO of a semiconductor laser excitation solid laser 2. The control device 1A comprises: a beam splitter 11A for branching a laser light emitted from the semiconductor laser excitation solid laser 2 into the output light LO and a control light LC; a light reception element 12 for detecting the light quantity of the control light LC branched by the beam splitter 11A; and control means 13 for controlling the light quantity of the laser light emitted from the semiconductor laser excitation solid laser 2 so that the light quantity detected by the light reception element 12 will be constant. The beam splitter 11A has a transmittance and a reflectivity not depending on the polarization characteristic of the laser light.

Abstract: A method and apparatus may comprise a line narrowed pulsed excimer or molecular fluorine gas discharge laser system which may comprise a seed laser oscillator producing an output comprising a laser output light beam of pulses which may comprise a first gas discharge excimer or molecular fluorine laser chamber; a line narrowing module within a first oscillator cavity; a laser amplification stage containing an amplifying gain medium in a second gas discharge excimer or molecular fluorine laser chamber receiving the output of the seed laser oscillator and amplifying the output of the seed laser oscillator to form a laser system output comprising a laser output light beam of pulses, which may comprise a ring power amplification stage.

Abstract: To provide a laser processing apparatus compatible with increase in the output of the pumping light source without increasing the reflectance of the output mirror.

Abstract: A mode-locked laser device includes a Fabry-Perot resonator, a mode-locking element disposed within the resonator, a solid-state laser medium disposed within the resonator, and exciting means for applying excitation light to the solid-state laser medium. The opposite ends of the resonator, the mode-locking element and the solid-state laser medium are disposed to provide an average beam diameter of lasing light of not more than 150 ?m on the mode-locking element and an average beam diameter of the lasing light of not more than 200 ?m within the solid-state laser medium.

Abstract: An optically pumped, surface-emitting semiconductor laser having a mode-selective apparatus (7) which is intended for suppression of predeterminable, higher resonator modes of the semiconductor laser. The mode-selective apparatus is arranged in the beam path of a pump beam source (2) of the surface-emitting semiconductor laser.

Abstract: A laser device with frequency conversion, the device comprising a complex optical cavity comprising two cavity parts with two different levels of circulating intracavity power wherein there is placed at least one non-linear crystal (30) is placed within the cavity part of higher circulating power and an active medium (21) in the cavity part of lower circulating power, the power enhancement achieved in two steps and the total enhancement being the product of the enhancement factors in each step, providing additional freedom in design allowing both the condition for high enhancement of the interacting laser power inside the intracavity non-linear crystal and the condition for maximum power output from the laser to be satisfied simultaneously and wherein said complex optical cavity the first cavity part provides the initial step of power enhancement and comprises at least a laser cavity back mirror (20), highly reflective about a laser radiation fundamental frequency ?, and an active (gain) medium.

Abstract: A robust scalable laser. The laser includes plural fiber laser resonators. A cavity that is external to the fiber laser resonators combines plural laser beams output from the plural fiber laser resonators into a single output laser beam. In a specific embodiment, the plural fiber laser resonators are eye-safe double-clad Er:YAG laser resonators that are pumped via laser diode arrays.

Abstract: In a laser device, a crystal array includes a laser gain crystal and an optically non-linear frequency conversion crystal. A pump source couples at least two mutually spatially separated pump beams into the crystal array. Between two pump beams, a saw kerf of the crystal array extends parallel to the pump beams.

Abstract: A surface emitting laser (SEL) with an integrated absorber. A lower mirror and an output coupler define a laser cavity of the SEL. A monolithic gain structure positioned in the laser cavity includes a gain region and an absorber, wherein a saturation fluence of the absorber is less than a saturation fluence of the gain region.

Abstract: In a solid-state laser amplifier including at least two laser-active media in a common laser radiation field, the laser-active media do not form a hard aperture for the laser radiation field. Each of the laser-active media define a plane that is penetrated by the laser radiation field. The laser amplifier includes at least one focusing optical element disposed in the laser radiation field between two adjacent laser-active media. A focal length and a distance of the focusing optical element from the planes of the two adjacent laser-active media are selected such that the planes of the laser-active media are approximately mapped onto each other by a near-field far-field transformation.

Abstract: A method of modulation terahertz radiation comprising: (A) generating Terahertz radiation by pumping nonequilibrium electrons into a Magnon Gain Medium (MGM), wherein propagation of nonequilibrium electrons in the MGM causes generation of nonequilibrium magnons, and wherein interaction between the nonequilibrium magnons causes generation of the Terahertz radiation; and (B) frequency modulating THz radiation generated in the MGM by applying longitudinal AC magnetic field, or by applying AC electrical field bias.

Abstract: A mode-locked laser device includes a Fabry-Perot resonator, a mode-locking element disposed within the resonator, a solid-state laser medium disposed within the resonator, and exciting means for applying excitation light to the solid-state laser medium. The opposite ends of the resonator, the mode-locking element and the solid-state laser medium are disposed to provide an average beam diameter of lasing light of not more than 150 ?m on the mode-locking element and an average beam diameter of the lasing light of not more than 200 ?m within the solid-state laser medium.

Abstract: Provided is a pump laser integrated vertical external cavity surface emitting laser (VECSEL). The VECSEL may include a surface emitting laser unit including a first active layer having a multiple quantum well structure emitting light having a first wavelength, a reflective layer may be formed on the first active layer, and an external mirror may be disposed opposite to a lower surface of the first active layer and defining a cavity resonator together with the reflective layer. A pump laser unit may be formed on a part of the surface emitting laser unit and may have a perpendicular light emissive surface emitting a pump beam having a second wavelength for exciting the first active layer. A beam reflector may be formed on the light emissive surface of the pump laser unit and reflecta pump beam that is incident from the pump laser unit to the first active layer.

Abstract: A pumping system for a laser source includes a pump diode that emits a pump beam having a central wavelength that varies with temperature. A selective mirror having a plurality of spectral reflectivity peaks, corresponding to a plurality of predetermined wavelengths, locks the operation of the pump diode onto one of the predetermined wavelengths in accordance with temperature.

Abstract: A side-pumped, diode-pumped solid-state laser cavity includes a conductively cooled housing having an opening O for pump radiation from a diode array in close proximity to a laser rod. The pump light is absorbed by the rod and excites the laser ions. The cavity includes a thin, diffuse reflector encircling the rod, having a shaped opening for the collection and redirection of the pump light into the rod, and a good heat conductor as the heat sink and heat conductor. A split heat sink inhibits the flow of heat from the pump diodes into the laser rod, and pre-formed air spacings are designed to provide uniform temperature distribution around the laser rod.

Abstract: A laser device and a method of pumping a laser gain medium (R) comprise directing pulses of laser light from a pump laser (10) to a series of separate locations (11, 12, 13, 14, 15, 16 and 17) arranged longitudinally along the gain medium (R) in the direction of laser propagation. Each pulse of laser light generates a population inversion in an associated portion of the gain medium (R) just ahead of the laser photons. The pulses from the pump laser (10) are transmitted by a splitter (18) to the series of separate locations by optical delay lines (11, 12, 13, 14, 15, 16 and 17) and each delay line is arranged to pump a different portion of the gain medium to cause a localised population inversion. The pulse transmission delays deliver a sequence of pulses to the portions of the gain medium (R) such that each portion will in turn contribute to amplification of a laser propagating within the gain medium (R).

Abstract: A vertical external cavity surface emitting laser is provided that is integrally mounted on a single heat sink together with a pump laser. In the surface emitting laser, a laser chip has a gain structure to emit light at a predetermined wavelength and it is disposed on a center portion of a top surface of a heat sink, an external mirror is spaced apart from the laser chip at a predetermined distance to transmit a portion of the light emitted from the laser chip to an outside and to reflect the remaining portion of the light to the laser chip, a pump laser is disposed on one side of a top surface of the heat sink to emit pump light in a horizontal direction for activating the laser chip, and a reflection mirror is disposed on the other side of the top surface of the heat sink opposite to the pump laser to reflect the pump light emitted from the pump laser to the laser chip.

Abstract: Electron-beam-pumped semiconductor ultra-violet optical sources (ESUVOSs) are disclosed that use ballistic electron pumped wide bandgap semiconductor materials. The sources may produce incoherent radiation and take the form of electron-beam-pumped light emitting triodes (ELETs). The sources may produce coherent radiation and take the form of electron-beam-pumped laser triodes (ELTs). The ELTs may take the form of electron-beam-pumped vertical cavity surface emitting lasers (EVCSEL) or edge emitting electron-beam-pumped lasers (EEELs). The semiconductor medium may take the form of an aluminum gallium nitride alloy that has a mole fraction of aluminum selected to give a desired emission wavelength, diamond, or diamond-like carbon (DLC). The sources may be produced from discrete components that are assembled after their individual formation or they may be produced using batch MEMS-type or semiconductor-type processing techniques to build them up in a whole or partial monolithic manner, or combination thereof.

Abstract: An optical apparatus comprising a gain medium exhibiting polarisation dependent absorption along two axes, the gain medium having a weakly absorbing axis and a strongly absorbing axis, an optical pump source arranged to direct pump light towards a first face of the gain medium such that the pump light entering the gain medium has a component of its polarisation parallel to the weakly absorbing axis, a polarisation modifying apparatus and one or more reflectors which are together arranged to modify the polarisation of pump light which exits the gain medium through a second face of the gain medium, and to direct the pump light with modified polarisation back towards said second face of the gain medium.

Abstract: The laser radiation apparatus is provided having substantial light emission intensity although the laser radiation apparatus is miniaturized. A solid state laser rod; the excitation light source formed such that the excitation light source surrounds an emission axis in a section perpendicular with respect to the emission axis of laser light of the solid state laser rod; and a lens barrel placed so that the lens barrel surrounds the excitation light source and condenses light from the excitation light source to the solid state laser rod. Excitation light reflected upon inner surface of the lens barrel is radiated uniformly over the lateral surface of the laser rod so that laser active medium is efficiently excited, and energy conversion rate is improved.

Abstract: A laser arrangement comprising a first and a second resonant cavity for generating a first and a second fundamental wavelength. A first and a second non-linear region are provided in the second cavity for sum-frequency mixing of the radiation generated in the first cavity and in the second cavity, and for frequency-doubling of the radiation generated in the second cavity, respectively.

Abstract: The invention provides systems and methods enabling high fidelity quantum communication over long communication channels even in the presence of significant loss in the channels. The invention involves laser manipulation of quantum correlated atomic ensembles using linear optic components (110, 120), optical sources of low intensity pulses (10), interferers in the form of beam splitters (150), and single-photon detectors (180, 190) requiring only moderate efficiencies. The invention provides fault-tolerant entanglement generation and connection using a sequence of steps that each provide built-in entanglement purification and that are each resilient to realistic noise levels. The invention relies upon collective rather single particle excitations in atomic ensembles and results in communication efficiency scaling polynomially with the total length of the communication channel.

Abstract: An optical system comprises optical pump lasers, depolarizing filters and a multiplexer. A plurality of optical pump lasers generates a plurality of initial optical signals at different wavelengths. A plurality of depolarizing filters depolarize the plurality of initial optical signals. A multiplexer multiplexes the plurality of initial optical signals to form at least one optical pump signal. These systems and methods advantageously provide at least one optical pump signal with the required energy spread across multiple polarizations with fewer optical pump lasers. The reduction of optical pump lasers may eliminate the need to balance or adjust the power and polarization of each optical pump laser. Further, by reducing the number of optical pump lasers, the rate of component failure also reduces. As a result, these systems and methods are more reliable, may reduce maintenance costs, and may reduce the size as well as weight of the optical pumping system.

Abstract: Solid-state laser(s) pumped by incoherent, monochromatic light from sources such as LED arrays and integrating technologies such as high power LED arrays and solid-state laser materials in conjunction with efficient and uniform absorption of pumping energies through a diffusing pump chamber. The resulting laser(s) are compact, robust, low-cost, and able to produce high power output for practical applications. It may efficiently operate over wide temperature and performance ranges, at CW or pulse modes, even with ultra short pulse width and/or extremely high repetition rates. Our inventive structure(s) is/are highly flexible and applicable to a large group of lasing media including those with very short upper state life times. Advantageously, they may be applied to a plethora of laser systems at wavelengths that have important applications and unavailable to other direct pumping technologies.

Abstract: The present invention uses an intra-cavity modulation approach to modulate a laser transmitter at bandwidths greater than a few gigahertz (GHz) in a non-ambiguous waveform by chirping the laser and simultaneously mode locking. Accordingly, the inventive system includes a source of a beam of electromagnetic energy; a mechanism for mode locking the beam; and an arrangement for chirping the beam. In the illustrative embodiment, the source is a laser. The mode locking mechanism may be an active element or a passive element. The beam is chirped with a translation mirror. The translation mirror may be driven with a piezo-electric drive coupled. In the best mode, the carrier is chirped with an electro-optical crystal disposed in the cavity of the laser. The laser is chirped to the free-spectral range limit, which is typically a few hundred megahertz, by scanning the optical length of the laser resonator.

Abstract: The side-pumped solid-state laser source comprises a resonant cavity defined by at least two spaced-apart mirrors, an active medium of laser crystal type placed in said resonant cavity, and a pumping source, the layout of the resonant cavity, defined by the crystal and by the mirrors, being arranged to cause spatial inversion of the oscillating mode within the active medium in the absorption direction of the pumping beam, such as to symmetrize the thermal focal length seen by the oscillating mode. The laser source comprises lenses for conditioning the pumping beam emitted by the pumping source, to form on the side face of the laser crystal a pumping spot arranged to symmetrize the spatial quality of the emitted laser beam and/or active control means for the laser crystal temperature, in order to correct its undesired astigmatic effects.

Abstract: A laser includes a Ti:sapphire gain-element that is optically pumped by radiation from a semiconductor laser device. In one example the semiconductor laser device is an InGaN diode-laser array and the gain-element is optically pumped by radiation emitted by that array. In another example, the semiconductor laser device is an optically pumped semiconductor laser (OPS-laser) optically pumped by radiation from an InGaN diode-laser array. In a further example the semiconductor device is an intracavity frequency-doubled OPS laser.

Abstract: A lighting system includes a microwave resonator (2) for generating a standing microwave in the internal space, and a gas cell (6) enclosing a medium is disposed in the internal space of the microwave resonator 2. The lighting system excites the medium in the gas cell (6) by the standing microwave to generate light. The gas cell (6) is replaceably mounted on the microwave resonator (2). The generated light is output to the outside of the microwave resonator (2) through a light lead-out hole (26). Thereby, it is possible to provide a lighting system (including a gas laser) capable of emitting light efficiently with a compact and inexpensive device configuration and of achieving a long life. Moreover, it can also be used as a lighting system in the THz-wave region by enclosing the medium for generating light in the far-infrared region in the gas cell (6).

Abstract: An improved tube solid-state laser (SSL) is provided utilizing diode pumping, microchannel cooling, optics, and/or new coating and bonding processes. In one example, an amplifier module for the SSL includes a tube of laser gain material, a first substrate and a second substrate including microchannels adjacent an interior and exterior surface of the tube, respectively, and a plurality of diode bars arranged exterior to the second substrate. Advantageously, thermal lensing effects, birefringence, bifocussing, and alignment problems associated with typical tube SSLs are eliminated or reduced while providing high beam quality and high average power levels.

Abstract: An apparatus for optically pumping a laser-active solid body with pumping light coupled into the solid body through an end surface of the solid body is disclosed. The apparatus includes a laser-active solid body including an end surface though which pumping light is coupled into the solid body and a lateral surface through which pumping light exits the solid body, a reflector surrounding the laser-active solid body at a distance from the lateral surface of the solid body for reflecting light that exists the solid body back towards the solid body, and a surface for diffusing light that is coupled into the solid body through the end surface of the solid body and that exits the solid body through the lateral surface. The surface is selected from the group consisting of the lateral surface and a surface of the reflector.

Abstract: Corner pumping method and gain module for high power slab laser are disclosed. In one embodiment, said method comprises directing a pump light from one or more pump light sources each consisting of a high power diode array and its coupling system into a laser slab through prior cut slab corners of said laser slab without restriction to the incident angle or the polarization state of the pump light, wherein said laser slab includes an undoped circumambient portion and one or more doped central portions; propagating said pump light within the laser slab by total internal reflection (TIR), wherein said pump light firstly pass said undoped circumambient portion, secondly pass said doped central portion, thirdly pass said undoped circumambient portion again, and fourthly take inner reflection at the surface of said undoped circumambient portion, and by repeating these steps, achieve multi-pass absorption; and substantially absorbing the pump light during propagating.

Abstract: A solid state pump cavity comprising a laser rod encased by diffusion bonding inside an outer cladding. The outer cladding provides the ability to efficiently conduct heat away from the laser rod. The outer cladding is also configured to absorb spontaneous laser radiation that would otherwise be re-amplified by the laser rod. Diffusion bonding of the outer cladding to the laser rod forms a seamless optical boundary between the outer cladding and the laser rod. An alternative embodiment of the pump cavity comprises multiple segments of laser rod and outer cladding assemblies coupled together with undoped sections that are diffusion bonded to the ends of the laser rod and outer cladding assemblies.

Abstract: A lasing apparatus includes a laser medium and a pump source. The laser medium includes one of a Holmium-doped fluoride crystal or a Holmium-doped fluorozirconate ZBLAN glass fiber. The pump source generates pulses that resonantly pump the laser medium such that the laser medium produces an output from the 5I5 level to the 5I7 level of Holmium. The pump source produces pulses having a duration that is at least as long as a storage time of the 5I5 level of the laser medium. The pump source pumps the laser medium with signals having a wavelength shorter than 1.67 ?m, with the laser medium producing an output having a wavelength of about 1.67 ?m.

Abstract: Provided is a millimeter-wave band frequency optical oscillator that can be used as an oscillation frequency signal source for a millimeter-wave forwarded to wireless subscribers from a base station of a millimeter-wave wireless subscriber communication system for a next generation (e.g., fifth generation) ultra-high speed wireless internet service. A pair of an optical fiber amplifier and an optical fiber grating mirror is connected to each of input/output ports of a loop mirror in parallel, so that a dual mode laser resonator is formed which can make simultaneous oscillation in two laser modes suitable for each wavelength. Accordingly, it is possible to obtain a light source that is modulated to a ultra-high frequency (over 60 GHz) by a beat phenomenon between the two laser modes.

Abstract: Apparatus and methods for high fidelity quantum communication over long communication channels even in the presence of significant loss in the channels are disclosed. The invention employs laser manipulation of quantum correlated atomic ensembles using linear optic components, optical sources of low intensity pulses, beam splitters, and single-photon detectors requiring only moderate efficiencies. The invention provides fault-tolerant entanglement generation and connection, using a sequence of steps that each provide built-in entanglement purification and that are each resilient to the realistic noise. The invention relies upon collective excitation in atomic ensembles rather than single particle excitations in atomic ensembles so that communication efficiency scales polynomially with the total length of a communication channel.

Abstract: A method for increasing the efficiency of generating lasers by pumping two separate wavelengths into an erbium-based medium to populate the 4I11/2 state and depopulate the 4I13/2 state. A first excitation wavelength region is located between approximately 955 nm to approximately 1100 nm. The second excitation wavelength region is located between approximately 1600 nm to approximately 1850 nm. This multi-wavelength pumping scheme may be operated in continuous wave or quasi-continuous wave mode.

Abstract: A master oscillator power amplifier (MOPA) laser system includes a symmetrical master oscillator and an amplifier each having an optically pumped solid-state gain rod. An optical relay is located between the laser resonator and the amplifier gain rod. When the oscillator and amplifier gain media are equally optically pumped, the magnification and the distances from the optical relay to the resonator and the amplifier gain rod can be selected such that amplifier efficiency is maximized, independent of optical pump power, even if the diameters of the oscillator and amplifier gain rods are different.

Abstract: In a miniature Q-switched, pulsed laser, having a two arm folded resonator, Q-switching is effected by rapidly and reciprocally tilting a resonator mirror of the laser about an axis perpendicular to the axis of the laser resonator. The angular excursion of the tilting and the frequency of the tilting are selected cooperative with dimensions of the resonator to maximize energy and symmetry of intensity distribution in Q-switched pulses delivered by the laser. Rapid reciprocal tilting of the mirror is accomplished using a piezoelectrically-driven, MEMS scanner operated in a resonant mode.

Abstract: A compact and efficient ultraviolet laser source based on a optically-pumped solid-state or fiber laser that produces near-infrared output light suitable for nonlinear frequency conversion. The infrared laser output is frequency tripled or quadrupled to produce light in the ultraviolet wavelength range (200 nm to 400 nm). The novel technology is the use of highly efficient periodically poled nonlinear crystals, such as stoichiometric and MgO-doped lithium tantalate and lithium niobate. As opposed to conventional frequency-converted UV laser sources, which have high power consumption, high cost, and low efficiency, the laser sources of this invention utilize high efficiency nonlinear conversion provided by periodically poled materials and allow lower-cost architectures without additional focusing lenses, high power pump diodes, etc.

Abstract: Conventionally, a laser beam is amplified by making a single pass through an amplifier but the laser beam emitted from the oscillator generally has low energy, so the energy stored in the amplifier cannot be fully extracted and only low laser output power and overall efficiency result. According to the method of the invention for amplifying a solid-state laser, the laser beam is passed through the amplifier multiple times and with spatial uniformity so as to achieve efficient extraction of the energy stored in the amplifier and the thermally induced distortion of the laser beam can be compensated by the single amplifier.

Abstract: A semiconductor light-emitting device includes a semiconductor light-emitting thin film, the thickness h of which satisfies the following conditional equation: 0.9 × ( 2 ? m + 1 ) ? ? 0 4 ? n ? h ? 1.1 × ( 2 ? m + 1 ) ? ? 0 4 ? n and m in the conditional equation satisfies the following conditional equation: 2 ? m + 1 m ? ( m + 1 ) ? ? 0 2 > ? where ?0 is a center wavelength of light generated in the semiconductor light-emitting thin film, n is a refractive index of the semiconductor light-emitting thin film, m is 0 or a positive integer, and ? is a half bandwidth of a light emission spectrum when there is no interference between light rays generated in the semiconductor light-emitting thin film.

Abstract: A conventional method for a solid-state laser device that obtains a laser beam output of a high quality at a high output using a laser diode as a pumping light source has a problem that the costs are increased and the fabrication becomes complicated due to an increasing number of components, such as a diffusing reflection mirror, a condenser lens, and a holding mechanism and a cooling mechanism thereof. Coating with a antireflection coating to reduce a transmission loss of laser diode light, and coating with a high reflection coating to reflect the laser diode light are provided alternately on the outer surface of a cooling tube. Also, an irradiation direction of the laser diode is not directed to the center of the laser rod, but is given with a certain angle to be positively tilted. This configuration makes it possible to eliminate the above problem.

Abstract: An efficient, powerful and reliable system for amplifying optical pulses. Seed-pulses are generated by a seed-pulse source and are transmitted to an optical amplifier for amplification. The power for the amplification is provided by a Q-switched, diode-pumped, intracavity-doubled pump laser.