Abstract: A monoblock laser cavity incorporates optical components for a short-pulse laser. These optical components are ‘locked’ into alignment forming an optical laser cavity for flash lamp or diode laser pumping. The optical laser cavity does not need optical alignment after it is fabricated, increasing the brightness of the monoblock laser.

Abstract: A composite optical waveguide 1 includes a first optical waveguide 9 comprising a silica-based core and a second optical waveguide 11 comprising an Si-based core. The second optical waveguide 11 is joined to the first optical waveguide 9. The length of the first optical waveguide 9 corresponds to a permissible propagation loss of the second optical waveguide 11. The second optical waveguide 11 includes a sharply curved portion 13 having a radius smaller than the minimum bend radius of the first optical waveguide 9.

Abstract: A compact solid state laser that generates multiple wavelengths and multiple beams that are parallel, i.e., bore-sighted relative to each other, is disclosed. Each of the multiple laser beams can be at a different wavelength, pulse energy, pulse length, repetition rate and average power. Each of the laser beams can be turned on or off independently. The laser is comprised of an optically segmented gain section, common laser resonator with common surface segmented cavity mirrors, optically segmented pump laser, and different intra-cavity elements in each laser segment.

Abstract: The multi-channel optical device includes multiple laser cavities that each reflects a different light channel back and forth between reflective components. One of the reflective components is common to all of the laser cavities in that the common reflective component receives the channels from each of the laser cavities and reflects the received channels. The laser cavities also share a multiplexer that receives the channels reflected by the common reflective device and demultiplexes the channels into demultiplexed channels. A portion of the reflective components are partial return devices that each receives one of the demultiplexed channels. Each of the partial return devices transmits a portion of the demultiplexed channel received by that partial return device. The transmitted portion of the demultiplexed channel exits the laser cavity. Additionally, each of the partial return devices reflects a portion of the demultiplexed channel receive by that partial return device.

Abstract: A laser amplifier arrangement includes an optical pump source and an axially arranged laser oscillator-amplifier configuration pumped by the pump radiation. The laser oscillator-amplifier configuration includes a laser oscillator excitable by a portion of the pump radiation to emit a laser beam, and a laser amplifier that amplifies the laser beam using the pump radiation. The laser oscillator and laser amplifier are arranged in a substantially coaxial or collinear manner relative to a longitudinal axis of the laser oscillator-amplifier configuration. The pump source includes a first beam source for producing a first pump radiation to pump the laser oscillator, a second beam source for producing a second pump radiation for the laser amplifier, and a pump radiation conducting device, by means of which both the first and the second pump radiation can be lead into the laser oscillator-amplifier configuration substantially in the direction of the longitudinal axis for longitudinal pumping.

Abstract: Fiber-laser light is Raman shifted to eye-safer wavelengths prior to spectral beam combination, enabling a high-power, eye-safer wavelength directed-energy (DE) system. The output of Ytterbium fiber lasers is not used directly for spectral beam combining. Rather, the power from the Yb fiber lasers is Raman-shifted to longer wavelengths, and these wavelengths are then spectrally beam combined. Raman shifting is most readily accomplished with a “cascaded Raman converter,” in which a series of nested fiber cavities is formed using fiber Bragg gratings.

Abstract: A compact solid state laser that generates multiple wavelengths and multiple beams that are parallel, i.e., bore-sighted relative to each other, is disclosed. Each of the multiple laser beams can be at a different wavelength, pulse energy, pulse length, repetition rate and average power. Each of the laser beams can be turned on or off independently. The laser is comprised of an optically segmented gain section, common laser resonator with common surface segmented cavity mirrors, optically segmented pump laser, and different intra-cavity elements in each laser segment.

Abstract: A wavelength-variable light source according to the present invention includes 2×2 3-dB directional coupler 3, closed loop-type optical circuit 5, at least two resonators 1 and 2, and optical amplifier 4. The closed loop-type optical circuit 5 is formed by connecting ends of the two output paths of 3-dB directional coupler 3. The resonators 1 and 2 have different resonance wavelength periods. One end of optical amplifier 4 is optically connected to one input path end 6 of 3-dB directional coupler 3. Lasing light is output from the other end of the optical amplifier 4. A non-reflecting structure is formed at the other input path end 7 of the 3-dB directional coupler. The wavelength-variable light source configured as described above includes an element configured to vary the resonance wavelength of the resonator 1 or 2.

Abstract: An electromagnetically responsive element includes sets of arrangements of self-resonant bodies, such as atoms or quantum dots that form an effective dielectric constant, typically at or near a resonance.

Abstract: A radiation system includes a target material supply configured to supply droplets of target material along a trajectory, and a laser system that includes an amplifier and optics. The optics are configured to establish a first beam path which passes through the amplifier and through a first location on the trajectory, and to establish a second beam path which passes through the amplifier and through a second location on the trajectory. The laser system is configured to generate a first pulse of laser radiation when photons emitted from the amplifier are reflected along the first beam path by a droplet of target material at the first location on the trajectory. The laser system is configured to generate a second pulse of laser radiation when photons emitted from the amplifier are reflected along the second beam path by the droplet of target material at the second location on the trajectory.

Abstract: An electromagnetically responsive element includes sets of arrangements of self-resonant bodies, such as atoms or quantum dots that form an effective dielectric constant, typically at or near a resonance.

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 .omega., and an active (gain) medium.

Abstract: A laser light source 1 is provided with a first reflection mirror 11, a laser medium 12, an aperture 13, an output mirror 14, a half mirror 15, a light beam diameter adjuster 16, and a second reflection mirror 17, and outputs laser oscillation light 31 reflected by the half mirror 15 to the outside. The main resonator is composed by the first reflection mirror 11 and the output mirror 14 disposed so as to be opposed to each other with the laser medium 12 placed therebetween. The external resonator is composed by the output mirror 14 and the second reflection mirror 17 disposed so as to be opposed to each other. The second reflection mirror 17 is configured such that it gives amplitude or phase variations to respective positions in the section of a light beam when the light is reflected, the second reflection mirror presents an amplitude or phase variation distribution, and determines the transverse mode of the laser oscillation light 31 based on the amplitude or phase variation distribution.

Abstract: A semiconductor laser device includes: a semiconductor laser having a reflector region, a gain region for laser oscillation and a plurality of refraction index controllers, the reflector region having a plurality of segments in which a diffraction region and a space region are coupled to each other, the plurality of segments being separated into a plurality of segment groups having a same optical length, the plurality of refractive index controllers being provided according to each segment group and controlling an equivalent refraction index of each segment group; a wavelength controller controlling an oscillation wavelength of the semiconductor laser by controlling the plurality of the refraction index controllers as at least one of control parameters; and a dither controller inputting a dither signal into only one of the segment groups having the most segments from one of the refractive index controllers according to the segment group.

Abstract: A light emitting device includes first and second cladding layers and an active layer therebetween including first and second side surfaces and first and second gain regions, a second side reflectance is higher than a first side reflectance, a first end surface part of the first gain region overlaps a second end surface part of the second gain region in an overlapping plane, the first gain region obliquely extends from the first end surface to a third end surface, the second gain region obliquely extends from the second end surface to a fourth end surface, a first center line connecting the centers of the first and third end surfaces and a second center line connecting the centers of the second and fourth end surfaces intersect, and the overlapping plane is shifted from the intersection point toward the first side surface.

Abstract: A diode-pumped solid state pulsed laser includes an intracavity nonlinear crystal for wavelength conversion by difference frequency mixing and a secondary resonant cavity containing an additional nonlinear crystal for parametric amplification. Primary and secondary cavities are capable of injection seeding and wavelength stabilization resulting in a very narrow, stable, and well defined spectral output. The combination of pump diode pulsing, the implementation of the intracavity parametric oscillator and parametric amplifier results in very efficient operation. Optical fiber coupled parametric oscillator byproduct light allows simple and non-invasive wavelength diagnostics and monitoring upon connection to an optical spectrum analyzer.

Abstract: A laser device includes an outcoupling mirror, a laser medium, a phase-conjugate mirror based on stimulated Brillouin scattering, and an end mirror all arranged along an optical axis of the laser device. A controllable modulator is positioned between the phase-conjugate mirror and the end mirror. The outcoupling mirror and the end mirror form a start cavity. The outcoupling mirror and the phase-conjugate mirror form a main cavity.

Abstract: A tunable laser includes an optical gain medium, a first resonator, a periodically tunable optical filter, and a second resonator in which light of a laser wavelength exhibits a round trip time T. The optical filter is arranged between the first resonator and the second resonator and is tuned with a period t. The period t is governed by t=(n/m) T, where n and m are integers and m/n is not an integer.

Abstract: The invention concerns an optical device comprising an optical source for emitting a light beam in a plurality of emitting wavelengths and at least one laser, each of said at least one laser including a holographic medium (MH), means for injecting (FO, MCS, MUX, CO, IO, AV) said light beam derived from said optical source into said at least one laser, said holographic medium (MH) being adapted to generate a laser in at least one oscillation mode, said at least one oscillation mode being determined by at least one excitation wavelength among the plurality of emitting wavelengths. The invention is characterized in that said optical source comprises a light source emitting simultaneously in said plurality of emitting wavelengths.

Abstract: A laser apparatus includes a plurality of pumps each of which is configured to emit a corresponding pump laser beam having a unique peak wavelength. The laser apparatus includes a spectral beam combiner configured to combine the corresponding pump laser beams into a substantially spatially-coherent pump laser beam having a pump spectrum that includes the unique peak wavelengths, and first and second selectively reflective elements spaced from each other to define a lasing cavity including a lasing medium therein. The lasing medium generates a plurality of gain spectra responsive to absorbing the pump laser beam. Each gain spectrum corresponds to a respective one of the unique peak wavelengths of the substantially spatially-coherent pump laser beam and partially overlaps with all other ones of the gain spectra. The reflective elements are configured to promote emission of a laser beam from the lasing medium with a peak wavelength common to each gain spectrum.

Abstract: Objects are achieved by an optical semiconductor device comprising: a structure 61 including a substrate 50, a diffraction grating 52a, an active layer 54 and a refractive index control layer 60; and an laser element 100 including an electrode 92a for the active layer, an electrode 92b for the refractive index control layer and an electrode 92c for switching, wherein a pre-bias current is previously supplied from the electrode 92a for the active layer to the active layer 54 in a state where a switching current is not supplied from the electrode 92c for switching to the active layer 54, and then while a current Idrive for activation is supplied from the electrode 92a for the active layer to the active layer 54, the laser element 100 is turned on by supplying the switching current Isw from the electrode 92c for switching to a part of the active layer 54, as well as turning off the laser element 100 by halting the supply of the switching current Isw.

Abstract: Method for generating a laser pulse for the fine machining of workpieces using a fiber laser, the laser fiber of which is optically pumped by use of at least one diode laser which is operated by a current pulse whose slew rate, pulse height, and pulse length are adjusted in adaptation to the laser fiber in such a way that the laser pulse (22) is initially composed of a primary relaxation pulse (A), independently of the pulse length of the current pulse.

Abstract: A semiconductor chip has at least two DFB etched facet laser cavities with one set of facets with AR coatings and a second set of etched facets with HR coatings that have a different relative position with respect to the gratings. This creates a difference in the phase between each of the etched facets and the gratings which changes the operational characteristics of the two laser cavities such that at least one of the lasers provides acceptable performance. As a result, the two cavity arrangement greatly improves the yield of the fabricated chips.

Abstract: A dual-cavity single longitudinal mode (SLM) laser oscillator generates a pulsed laser signal having a long pulsewidth, long coherence length, and good shot-to-shot energy stability. The laser oscillator has a first cavity between an output coupler and a rear mirror and a second cavity between the output coupler and an intra-cavity mirror disposed between the output coupler and rear mirror. High-loss cavity optics and a passive Q-switch achieve a very high number of round trips that reduce the number of cavity modes down to two or three. The dual cavity design further discriminates between the remaining modes and allows SLM operation. The laser oscillator and an amplifier can be used as a pump laser for a laser system that generates red, green, and blue pulses for holographic recording. A wavelength conversion stage uses optical parametric amplifier(s), doubling crystals, and sum-frequency mixers to produce RGB light from the pump pulses.

Abstract: Provided is a resonator of a hybrid laser diode. The resonator includes: a substrate including a semiconductor layer where a hybrid waveguide, a multi-mode waveguide, and a single mode waveguide are connected in series; a compound semiconductor waveguide, provided on the hybrid waveguide of the semiconductor layer, having a tapered coupling structure at one end of the compound semiconductor waveguide, the tapered coupling structure overlapping the multi-mode waveguide partially; and a reflection part provided on one end of the single mode waveguide. The multi-mode waveguide has a narrower width than the hybrid waveguide and the single mode waveguide has a narrower width than the multi-mode waveguide.

Abstract: A mode-locked laser employs a coupled-polarization scheme for efficient longitudinal pumping by reshaped laser diode bars. One or more dielectric polarizers are configured to reflect a pumping wavelength having a first polarization and to reflect a lasing wavelength having a second polarization. An asymmetric cavity provides relatively large beam spot sizes in gain medium to permit efficient coupling to a volume pumped by a laser diode bar. The cavity can include a collimation region with a controlled beam spot size for insertion of a saturable absorber and dispersion components. Beam spot size is selected to provide stable mode locking based on Kerr lensing. Pulse durations of less than 100 fs can be achieved in Yb:KGW.

Abstract: A laser system according to the invention comprises pump generating means (x02, x03) for generating at least a first and a second, preferably focused, pump beam, and lasing means (x06, x07) for emitting radiation by being appropriately pumped. The lasing means (x06, x07) is disposed in a first resonator so as to receive the first pump beam in order to generate a first beam (x21) having a first frequency, and the lasing means (x06, x07) is disposed in a second resonator so as to receive the second pump beam in order to generate a second beam (x22) having a second frequency. At least one Q-switch (x08; x17, x18) is disposed in the first and the second resonator, so that the first beam and the second beam both pass a Q-switch (x08; x17, x18). The laser system (x01) has an output (x13) generated from said first beam (x21) and said second beam (x22), and at least a part of said output (x13) is fed back to a regulation system (x14), said regulation system (x14) controlling said pump generating means (x02, x03).

Abstract: An optical waveguide device comprises a plurality of mirrors, wherein at least one mirror comprises a first and second reflective end that reflect and transmit light. The plurality of mirrors comprises at least one first material having at least one first refractive index; an axis line; a first cladding comprising a second material having a second refractive index; a second cladding, formed above the first, comprising a third material having a third refractive index; a core comprising a fourth material; and a plurality of core parts formed within at least one of the first or second claddings. The fourth material has a fourth refractive index that is greater than the second and third refractive indices and the core parts have a plurality of core part ends coupled to one of the reflective ends where at least one core part end is approximately parallel to one of the reflective ends.

Abstract: The invention relates to a two-stage laser system well fit for semiconductor aligners, which is reduced in terms of spatial coherence while taking advantage of the high stability, high output efficiency and fine line width of the MOPO mode. The two-stage laser system for aligners comprises an oscillation-stage laser (50) and an amplification-stage laser (60). Oscillation laser light having divergence is used as the oscillation-stage laser (50), and the amplification-stage laser (60) comprises a Fabry-Perot etalon resonator made up of an input side mirror (1) and an output side mirror (2). The resonator is configured as a stable resonator.

Abstract: Fundamental-wavelength pulses from a fiber a laser are divided into two portions and the two portions are separately amplified. One of the amplified fundamental-wavelength pulse-portions is frequency-doubled. The frequency doubled portion is sum-frequency mixed with the other amplified fundamental wavelength pulse-portions to provide third-harmonic radiation pulses.

Abstract: Methods and apparatus for broad tuning of single wavelength quantum cascade lasers and the use of light output from such lasers for highly sensitive detection of trace gases such as nitrogen dioxide, acetylene, and vapors of explosives such as trinitrotoluene (TNT) and triacetone triperoxide (TATP) and TATP's precursors including acetone and hydrogen peroxide. These methods and apparatus are also suitable for high sensitivity, high selectivity detection of other chemical compounds including chemical warfare agents and toxic industrial chemicals. A quantum cascade laser (QCL) system that better achieves single mode, continuous, mode-hop free tuning for use in L-PAS (laser photoacoustic spectroscopy) by independently coordinating gain chip current, diffraction grating angle and external cavity length is described. An all mechanical method that achieves similar performance is also described. Additionally, methods for improving the sensor performance by critical selection of wavelengths are presented.

Abstract: A high-power narrow-linewidth fiber laser system includes a seed oscillator with multiple resonant cavities and an amplifier stage. The seed oscillator includes a gain fiber, a pump source to introduce pump light into the gain fiber, a single-mode output fiber arranged at the end of the active gain fiber, a first resonant cavity including the active gain fiber, and a second resonant cavity including the active gain fiber. The first and second resonant cavities cooperate to minimize the synchronization of longitudinal modes and thereby reduce modal beating. The amplifier preferably includes an active multimode gain fiber capable of supporting a single fundamental mode at the signal wavelength, wherein the single mode output fiber of the seed oscillator and the multimode gain fiber of the amplifier are mode-matched and coupled without a mode converter.

Abstract: A laser is provided, suitable for use in laser displays, having a laser cavity defined by at least first and second mirrors, a lasing material positioned in an optical path within the cavity with an associated pumping source and wherein one of the mirrors has a reflective surface that is moveable so as to alter the length of the cavity at a rate sufficiently high to ensure that effects due to a speckle pattern, as perceived by an observer or detector of light generated by the laser, are reduced while preserving the instantaneous coherence of the laser light. Sufficiently rapid movement of the mirror surface ensures that any speckle pattern changes at a faster rate than can be detected by the human eye or by a detector so that speckle is no longer visible, or is at least considerably reduced.

Abstract: In a vertical cavity surface-emitting semiconductor laser device, first and second resonance wavelengths which are different are provided while a first resonator and a second resonator are coupled optically, and a gain of an active layer at the first resonance wavelength on the side of short wavelength is higher than that at the second resonance wavelength on the side of long wavelength. An absorption coefficient of an optical absorption layer when no electric field is applied is small for the first and second resonance wavelengths, and when an electric field is applied, an absorption coefficient of the optical absorption layer for the first resonance wavelength on the side of short wavelength is larger than that for the second resonance wavelength on the side of long wavelength.

Abstract: A laser system comprises first and second laser sub-cavities each including a gain medium arranged to produce volume gain gratings. The laser system further includes a beam combiner arranged to combine emission from each cavity and direct emission from one cavity to the other. As a result a stale, phase-locked coherently combined emission system is provided.

Abstract: A system, apparatus, and method may provide laser beams of two or more wavelengths from diode pumped solid-state laser sources (220, 222, 224). The beam paths of these laser beams with different wavelengths, which are generated by the laser sources (220, 222, 224), may be aligned along a common optical axis 280 by an optical configuration, to treat at least one target area. Frequency-doubled laser beams, output from a plurality of diode pumped solid state laser cavities, may be passed through fold mirrors (M2, M5, M8), and combined on a common optical axis 280, using one or more combiner mirrors (M10, M11, M12), to unify the beam paths. Selected laser beams may be delivered to a target using one or more delivery systems.

Abstract: An apparatus for producing coherent, pulsed ultraviolet light with pulse durations that range between 1 ps and 1 ?s includes one or more source lasers in the visible or near-infrared frequency range. The apparatus also includes one or more FC stages, at least one of the one or more FC stages including a nonlinear FC device and one or more optical elements. The optical elements include a reflector, a focusing element, a polarization-controlling optic, a wavelength separator, or a fiber optic component. The FC device includes a huntite-type aluminum double borate nonlinear optical material configured to produce FC light having a wavelength between 190 and 350 nm and a composition given by RAl3B4O12, where R comprises one or a plurality of elements {Sc, La, Y, Lu}. The nonlinear optical material is characterized by an optical transmission greater than 70% over the wavelength range of 190 to 350 nm.

Abstract: A tunable laser includes dispersion optics for separating generated laser pulses into first and second wavelength pulses directed along first and second optical paths. First and second reflective mirrors are disposed in the first and second optical paths, respectively. The laser's output mirror is partially reflective and partially transmissive with respect to the first wavelength and the second wavelength in accordance with provided criteria. A first resonator length is defined between the output mirror and the first mirror, while a second resonator length is defined between the output mirror and the second mirror. The second resonator length is a function of the first resonator length.

Abstract: An apparatus for producing coherent, continuous wave, ultraviolet light, includes one or more source lasers in the visible or near-infrared frequency range. The apparatus also includes one or more frequency conversion stages. Each of the one or more frequency conversion stages includes one or more reflectors, an optical resonator, one or more waveguide components, or one or more fiber optic components. At least one of the one or more frequency conversion stages includes a huntite-type aluminum double borate nonlinear optical material to produce light having a wavelength between 190 and 350 nm. The huntite-type aluminum double borate material has a composition given by MAl3B4O12, where M is one or a plural combination of elements {Sc, La, Y, or Lu}.

Abstract: A normally opaque waveguide interacting with a drop-filter cavity can be switched to a transparent state when the drop filter is also coupled to a dipole. This dipole induced transparency may be obtained even when the vacuum Rabi frequency of the dipole is much less than the cavity decay rate. The condition for transparency is a large Purcell factor. Dipole induced transparency can be used in quantum repeaters for long distance quantum communication.

Abstract: An active element for a laser source, the active element comprising an elongated bar with a reflective lateral surface, doped to be able to absorb at least a pumping beam being propagated at least approximately longitudinally in the bar in order to amplify at least a laser radiation also being propagated longitudinally; and a jacket in contact with the lateral surface of the bar and presenting a refractive index smaller than that of the bar, in the reflective lateral surface of the bar, there is at least one dull-ground diffusing zone able to interrupt the paths of spurious laser modes being propagated in the bar by total internal reflections on the lateral surface.

Abstract: An optical pulse stretcher and a mathematical algorithm for the detailed calculation of its design and performance is disclosed. The optical pulse stretcher has a plurality of optical cavities, having multiple optical reflectors such that an optical path length in each of the optical cavities is different. The optical pulse stretcher also has a plurality of beam splitters, each of which intercepts a portion of an input optical beam and diverts the portion into one of the plurality of optical cavities. The input optical beam is stretched and a power of an output beam is reduced after passing through the optical pulse stretcher and the placement of the plurality of optical cavities and beam splitters is optimized through a model that takes into account optical beam divergence and alignment in the pluralities of the optical cavities.

Abstract: A configuration for an unstable, negative branch imaging resonator (NBIR) is disclosed in which coupling mirrors are added so that the Primary and Secondary mirrors are not in direct optical communication with the imaging systems which minimizes the occurrence of the NBIR experiencing magnification runaway and/or odd order aberrations by using coupling mirrors to provide indirect optical communication between the imaging systems and the Primary and Secondary end mirrors.

Abstract: Disclosed is a laser system comprising: A laser assembly (101) comprising a plurality of emitters; first and second light feedback devices (208, 232) forming respective external cavities with the laser assembly; a dispersive device (205) for redirecting respective portions of the light from the laser assembly to the first and second feedback devices (208, 232), wherein the first feedback device (232) is adapted to reflect a feedback portion of the redirected beam back onto the dispersive device (205) and to generate the output beam (233) from an output part of the first redirected beam, —an imaging device (213) for generating an optical Fourier transform of the plurality of emitters at a Fourier plane (235). The dispersive device (205) is positioned displaced from said Fourier plane (235) by a predetermined displacement (d) in a direction along said principle axis (230).

Abstract: A system, apparatus, and method may provide laser beams of two or more wavelengths from diode pumped solid-state laser sources (220, 222, 224). The beam paths of these laser beams with different wavelengths, which are generated by the laser sources (220, 222, 224), may be aligned along a common optical axis 280 by an optical configuration, to treat at least one target area. Frequency-doubled laser beams, output from a plurality of diode pumped solid state laser cavities, may be passed through fold mirrors (M2, M5, M8), and combined on a common optical axis 280, using one or more combiner mirrors (M10, M11, M12), to unify the beam paths. Selected laser beams may be delivered to a target using one or more delivery systems.

Abstract: A laser light generating apparatus includes a laser light source, a phase-modulator, a signal generating unit configured to generate a modulation signal applied to the phase-modulator, a first external resonator, a second external resonator disposed at the stage succeeding the first external resonator, nonlinear optical elements each provided in the external resonators configured to implement wavelength conversion, an optical path length varying unit for varying the optical path length of each of the external resonators, and a control circuit having a negative feedback arrangement configured to obtain error signals for each of the external resonators, and configured to control the optical path length varying unit using the error signals according to FM sideband method. In the laser light generating apparatus, the external resonators are each held simultaneously in a resonance state by setting the frequency of the modulation signal and by controlling the optical path length of each of the external resonators.

Abstract: Semiconductor electrooptic medium shows behavior different from a medium based on quantum confined Stark Effect. A preferred embodiment has a type-II heterojunction, selected such, that, in zero electric field, an electron and a hole are localized on the opposite sides of the heterojunction having a negligible or very small overlap of the wave functions, and correspondingly, a zero or a very small exciton oscillator strength. Applying an electric field results in squeezing of the wave functions to the heterojunction which strongly increases the overlap of the electron and the hole wave functions, resulting in a strong increase of the exciton oscillator strength. Another embodiment of the novel electrooptic medium includes a heterojunction between a layer and a superlattice, wherein an electron and a hole in the zero electric field are localized on the opposite sides of the heterojunction, the latter being effectively a type-II heterojunction.

Abstract: A laser system for effective injection seeding is configured with a master oscillator lasing a narrowband seed radiation which is characterized by a single longitudinal master mode injected into a slave oscillator so that the latter generates a broadband slave radiation with a dominant slave mode and side slave modes. The slave radiation is coupled into an input of a SM fiber laser amplifier operative to output an amplified radiation with the spectra which is substantially as narrow as the spectra of the slave radiation.

Abstract: A surface emitting laser device is disclosed that is able to selectively add a sufficiently large loss to a high order transverse mode so as to efficiently suppress a high order transverse mode oscillation and to oscillate at high output in a single fundamental transverse mode. The surface emitting laser device includes a first resonance region that includes an active layer and spacer layers, two distributed Bragg reflectors that sandwich the resonance region, and a current confinement structure that defines a current injection region for the active layer. At least one of the distributed Bragg reflectors includes a second resonance region arranged in the current injection region excluding a predetermined region surrounding a center of the current injection region.

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.