Abstract: A laser beam is obtained from a semiconductor laser by a stable emission light amount. A first semiconductor laser is thermally coupled with a second semiconductor laser and driven by a feedback circuit constructed by a photodetector, an I-V converter, and a current generator so as to stabilize the emission light amount. A current I0? having a correlation with a drive current I0 of the 1st laser is outputted from a current mirror circuit. A modulation signal is supplied to a current pull-in type current driving circuit via a multiplier and a linearity compensating circuit and a current I2 according to the modulation signal is extracted from a collector of a transistor. The 2nd laser is driven by a current I1 (I0??I2) and a laser beam modulated by the modulation signal is generated. Since the signal modulation by the 2nd laser is performed without influencing on I0 and the 2nd laser is driven by I0?, the emission light amount is stabilized.

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.

Abstract: A laser apparatus includes a laser element that emits the laser beam. A detector detects the laser beam emitted from the laser element. A controller controls the laser element such that the laser beam is oscillated subject to multiple conditions, such as the emission frequency and the energy of the laser beam, when the laser element is in a ready state, based on the detection results. In the ready state, the laser beam is not emitted from the apparatus onto a subject. Closely monitoring the oscillated beam in the ready state allows the precise beam desired to be emitted in an operational mode. The apparatus is useful for fabricating semiconductor devices.

Abstract: Selectively oxidized vertical cavity lasers emitting at about 1290 nm using InGaAsN quantum wells that operate continuous wave below, at and above room temperature are reported. The lasers employ a semi-insulating GaAs substrate for reduced capacitance, high quality, low resistivity AlGaAs DBR mirror structures, and a strained active region based on InGaAsN. In addition, the design of the VCSEL reduces free carrier absorption of 1.3 ?m light in the p-type materials by placing relatively higher p-type dopant concentrations near standing wave nulls.

Abstract: A high power multi-frequency laser includes a laser cavity defined by reflective elements, a frequency routing device in the cavity comprising a plurality of frequency selective pathways, a first set of optical amplifiers optically coupled to a first end of the frequency routing device, and a second set of optical amplifiers optically coupling a second end of the frequency routing device and a first one of the reflective elements. The high power multi-frequency laser further includes a power combiner. The power combiner is optically coupled to the first set of optical amplifiers and a second one of the reflective elements and combines the outputs of the first set of optical amplifiers such that a common output for the multi-frequency laser is provided. The common output of the present invention provides a single output from the multi-frequency laser having a high output coupling efficiency.

Abstract: The light-emitting device comprises a substrate, an active region and a tunnel junction structure. The substrate comprises gallium arsenide. The active region comprises an n-type spacing layer and a p-type spacing layer. The tunnel junction structure comprises a p-type tunnel junction layer adjacent the p-type spacing layer, an n-type tunnel junction layer and a tunnel junction between the p-type tunnel junction layer and the n-type tunnel junction layer. The p-type tunnel junction layer comprises a layer of a p-type first semiconductor material that includes gallium and arsenic. The n-type tunnel junction layer comprises a layer of an n-type second semiconductor material that includes indium, gallium and phosphorus. The high dopant concentration attainable in the second semiconductor material reduces the width of the depletion region at the tunnel junction and increases the electrostatic field across the tunnel junction, so that the reverse bias at which tunneling occurs is reduced.

Abstract: A diode end-pumped solid state laser is provided which produces improved power output, long term stability and improved conversion efficiency from the pumping power, high as well as low power operation while maintaining certain desirable common characteristics such as TEM00 operation, circular outputs, readily aligned systems and compatibility with long lifetime for all components. The invention intracavity conversion to second, third and higher harmonics in several different spectral regimes. The invention also addresses the aspects of design flexibility, seeking in certain embodiments to provide a single platform for providing several harmonic beams.

Abstract: A semiconductor laser device has a current injection region (A) and current non-injection regions (B) located closer to respective laser beam-emitting end faces than the current injection region is. The semiconductor laser device has an oxide layer (106A) formed at a surface of a p-type (AlpHa1-p)qIn1-qP (0?p?x, 0?q?1) intermediate band gap layer (106) in each of the current non-injection regions (B), a p-type GaAs cap layer (107) formed on the intermediate band gap layer (106) in the current injection region (A), and a p-type GaAs contact layer (125) formed on the oxide layer (106A) and the p-type GaAs cap layer (107).

Abstract: A photonic crystal-based resonant cavity includes a first dielectric substance having a first dielectric permittivity, a plurality of second dielectric substances having a second dielectric permittivity and arranged in a first periodic structure with respect to at least one or more directions on a plane formed of the first dielectric substance, a plurality of third dielectric substances having a third dielectric permittivity and arranged in a second periodic structure with respect to at least one or more directions on the plane formed of the first dielectric substance, and disposed in unit cells formed by the plurality of second dielectric substances so as to be arranged in a third periodic structure together with the plurality of second dielectric substances, and one or more local defects formed to disrupt either the first periodic structure formed by the second dielectric substances or the second periodic structure formed by the third dielectric substances.

Abstract: A device and a process for integrating light energy transmit and/or receive functions with active devices such as GaAs or InP devices or light emitting devices, such as lasers. The device and process includes forming a passivation layer on top of the active device and forming a silicon photodetector on top of the passivation layer. The photodetector may be formed utilizing a standard solar cell growth process and may be formed as a mesa on top of the active or light-emitting device, thus forming a relatively less complicated semiconductor with an integrated monitoring device.

Abstract: Provided is a gas laser electrode in which a stable laser output can be obtained by inhibiting the deterioration of the electrode (discharge characteristics). In an anode 3, a dielectric material 4 is applied on the surface of a discharging portion 3a in order to inhibit the deterioration of the electrode. Used as a dielectric material 4 may be, for example, fluorides such as calcium fluoride and strontium fluoride. Further, the dielectric material 4 is of a thickness (in a range of 0.005 mm˜1.5 mm, preferably 0.1 mm˜1 mm, for example) sufficient to prevent the erosion of halogen gas in the discharging portion 3a of the anode 3 and to secure a conductivity thereof, whereby it is enabled to form mono-fluoride evenly in extreme precision.

Abstract: A pump fiber is stripped of its cladding over the last section. This can occur by etching a coating off. The sheath is preferably etched off wedge-shaped. As a result thereof, the remaining pump power is eliminated into the environment. How much stray pump light still proceeds via the fiber core to the fiber exit can be monitored over a length of the fiber completely stripped of the protective sheath.

Abstract: A photonic-crystal distributed-feedback laser includes a laser cavity with a waveguide structure that has a cavity length Lc and is bounded by two mirrors; an active region for producing optical gain upon receiving optical pumping or an input voltage; at least one layer having a periodic two-dimensional grating with modulation of a modal refractive index, the grating being defined on a rectangular lattice with a first period along a first axis of the grating and a second period along a second perpendicular axis of the grating, and wherein the grating produces three diffraction processes having coupling coefficients ?1?, ?2?, ?3?; and a lateral gain area contained within a second area patterned with the grating that has substantially a shape of a gain stripe with a width W, with the gain stripe tilted at a first tilt angle relative to the two mirrors.

Abstract: A semiconductor laser having a low beam divergence is disclosed. The laser includes at least one waveguide comprising an active layer generating an optical gain by injection of a current, a photonic band gap crystal having the refractive index modulation in the direction perpendicular to the propagation of the emitted light, and at least one defect. The active layer is preferably placed within the defect. The photonic band gap crystal and the defect are optimized such that the fundamental mode of laser radiation is localized at the defect and decays away from the defect, while the other optical modes are extended over the photonic band gap crystal. Localization of the fundamental mode at the defect results in the relative enhancement of the amplitude of the mode with respect to the other modes. Therefore, there is a larger confinement factor of the fundamental mode as compared to the confinement factor of the other modes. This enables efficient single-mode lasing from the laser having an extended waveguide.

Abstract: Apparatus for reducing spacing between a plurality of parallel, spaced apart plane-polarized laser-radiation beams delivered by a stack of laser-diode bars includes a ninety degree polarization rotator, and a compound prism including a total reflecting surface an internal polarization-selective surface parallel to each other. The polarization-selective surface is highly transmissive for radiation plane-polarized in one polarization orientation and highly reflective for radiation plane-polarized at ninety degrees to that orientation. The polarization rotator rotates the polarization of a portion of the beams. The beams are transmitted through the compound prism with the portion of polarization-rotated beams following a different path through the prism from that of the beams that are not polarization rotated. The beams exit the prism with spacing therebetween one-half of the spacing between beams entering the prism.

Abstract: A GaN series surface-emitting laser diode and a method for manufacturing the same are provided. The GaN series surface-emitting laser diode includes: an active layer; p-type and n-type material layers on the opposite sides of the active layer; a first-distributed Bragg reflector (DBR) layer formed on the n-type material layer; an n-type electrode connected to the active layer through the n-type material layer such that voltage is applied to the active layer for lasing; a spacer formed on the p-type material layer with a laser output window in a portion aligned with the first DBR layer, the spacer being thick enough to enable holes to effectively migrate to a center portion of the active layer; a second DBR layer formed on the laser output window; and a p-type electrode connected to the active layer through the p-type material layer such that voltage is applied to the active layer for lasing.

Abstract: This invention relates to a semiconductor laser device including a semiconductor laser element with an exit surface from which laser radiation can emerge, a collimating lens means which can reduce the divergence of the laser radiation emerging from the exit surface at least with respect to the first direction (Y) which is essentially perpendicular to the exit direction (Z) of the laser radiation, the semiconductor laser device furthermore including an auxiliary body which is permanently connected both to the semiconductor laser element and also to the collimating lens means. Furthermore, this invention relates to a semiconductor laser module of a semiconductor laser element, an auxiliary body and a collimating lens means and a process for producing the semiconductor laser means.

Abstract: An injection seeded modular gas discharge laser system capable of producing high quality pulsed laser beams at pulse rates of about 4,000 Hz or greater and at pulse energies of about 5 mJ or greater. Two separate discharge chambers are provided, one of which is a part of a master oscillator producing a very narrow band seed beam which is amplified in the second discharge chamber. The chambers can be controlled separately permitting separate optimization of wavelength parameters in the master oscillator and optimization of pulse energy parameters in the amplifying chamber. A preferred embodiment in an ArF excimer laser system configured as a MOPA and specifically designed for use as a light source for integrated circuit lithography. In the preferred MOPA embodiment, each chamber comprises a single tangential fan providing sufficient gas flow to permit operation at pulse rates of 4000 Hz or greater by clearing debris from the discharge region in less time than the approximately 0.25 milliseconds between pulses.

Abstract: A semiconductor laser includes an active layer formed on a substrate and a pair of cladding layers sandwiching the active layer. On at least one of resonator end faces of the semiconductor laser, a first dielectric film with hydrogen added therein is provided. Between the first dielectric film and the resonator end face, a second dielectric film for suppressing the diffusion of hydrogen is provided. Even when a semiconductor laser with an end face coating film including a hydrogen-added film is exposed to high temperatures, peeling of the end face coating film and deterioration of the end face coating film can be suppressed.

Abstract: A vertical laser cavity includes a non-planar top mirror in order to improve the optical performance of the laser cavity. In one approach, the top mirror is curved to form a plano-concave geometry with the bottom mirror, as opposed to the typical plano—plano geometry. This can reduce diffraction losses and otherwise improve optical performance.