Abstract: An object of the invention is to increase the beam diameter of a laser beam, and perform high-output wavelength conversion without causing crystal damage. A laser wavelength conversion device includes a laser wavelength conversion element for allowing incidence of a laser beam as a fundamental wave to convert a part of the fundamental wave laser beam into a wavelength-converted laser beam having a wavelength different from a wavelength of the fundamental wave laser beam. The laser wavelength conversion element includes a non-linear optical crystal having periodically polarization reversed portions. The polarization reversed portions are formed in such a manner that a region where a wavelength conversion efficiency is substantially uniform extends in a polarization direction of the non-linear optical crystal. The incident laser beam is converted into the wavelength-converted laser beam with the wavelength conversion efficiency.

Abstract: A multi-spectral laser system produces first and second output frequencies by nonlinear mixing of a first, second, and third laser light frequency in a single periodically polled crystal, where the first and second output frequencies are separated by a range greater than the degeneracy of the crystal.

Abstract: A robust, quickly tunable narrow-linewidth entangled photon source system based on Spontaneous Parametric Down Conversion (SPDC) of the pump light in periodically polled LiNbO3 (PPLN) waveguides. The photon source provides narrow-linewidth, entangled output photons having a wavelength in the telecom C-Band wavelength. To tailor the output spectrum of the output photons, the PPLN waveguide is arranged between two end waveguides having LiNbO3-embedded Bragg gratings, thereby forming a tunable Fabry-Perot cavity. The resulting narrow output linewidth of the output photons makes the system desirable for use in a long-distance quantum key distribution (QKD) system.

Abstract: A harmonics generating device has a periodic domain inversion structure 18 for converting a wavelength of laser beam to generate higher harmonics. An angle ? formed by a domain inversion plane P of the periodic domain inversion structure 8 and a propagation direction L of the laser beam is from 80 degrees to 89 degrees.

Abstract: In a branched resonator OPS-laser arrangement, a combination of intra-cavity optical parametric generation and intra-cavity sum-frequency mixing provides output radiation in a range between about 550 nanometers about 700 nanometers from an OPS fundamental wavelength in a range between about 900 nm and about 1100 nm.

Abstract: An optical output controller includes a wavelength conversion device operable to change the wavelength of pumped laser light; a heating/cooling unit operable to control the temperature of the wavelength conversion device; a temperature detector which detects the temperature of the wavelength conversion device; a temperature controller operable to control the heating/cooling unit such that the detected temperature corresponds to a target temperature; an optical output detector operable to detect the optical output from the wavelength conversion device; an optical-output maximization controller operable to determine a temperature at which the optical output is maximized according to the optical output detected by the optical output detector and from the detected temperature detected by the temperature detector and, further, outputs the temperature difference between the determined temperature and the detected temperature; and an adder which adds the temperature difference outputted from the optical-output maxim

Abstract: A vertical external cavity surface emitting laser (VECSEL) using end pumping in which a pumping beam is recycled using a pumping beam reflection layer to increase pumping beam absorption is provided. The VECSEL includes: an active layer for generating and emitting signal light; an external mirror that is separated from and faces a top surface of the active layer and transmits a first portion of the signal light and reflects a second portion of the signal light to the active layer; a first reflection layer contacting a lower surface of the active layer and reflecting the signal light to the external mirror; a pump laser for emitting the pumping beam toward the lower surface of the active layer to excite the active layer; and a second reflection layer contacting the top surface of the active layer and reflecting a portion of the pumping beam back to the active layer.

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 device for generating a high power frequency converted laser beam includes a nonlinear optical crystal having an entrance surface and a curved surface. The nonlinear optical crystal is configured to receive at least one laser beam at the entrance surface and provide a frequency converted beam through a frequency conversion process. The device also includes an optical coating coupled to the curved surface. The reflectance of the optical coating is greater than 50% at a wavelength of the frequency converted beam. Additionally, the far field divergence angle of the frequency converted beam increases after reflection off the curved surface. The device further includes a heat sink in thermal contact with the optical coating.

Abstract: There are provided a light source device and an image display apparatus. The light source device includes a first optical element that deflects a propagation direction of laser beams, a second optical element that separates laser beams, and a third optical element that defects the laser beams separated by the second optical element. The light source device further includes a light emitting unit that has one or more light emitting element emitting laser beams, an external resonator that reflects laser beams toward the first optical element and guides laser beams back to the light emitting unit, and a wavelength converting element that converts laser beams.

Abstract: A wavelength conversion laser 100 is provided with a solid-state laser having a cavity, and a wavelength converting element 6 arranged within the cavity. The solid-state laser includes two or more types of laser crystals 4 and 5 and oscillates solid-state laser light of multiple wavelengths. The wavelength converting element 6 converts the solid-state laser light of multiple wavelengths into light of second harmonic waves and sum-frequency wave of multiple wavelengths and simultaneously generates the second harmonic waves and sum-frequency wave of multiple wavelengths. The wavelength conversion laser 100 outputs converted wavelength light having a broad spectral width and low coherency, thereby enabling it to carry out highly efficient and stable high-output oscillation.

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 wavelength conversion laser light source includes: a non-linear optical crystal of an oxygen octahedral structure, having added thereto a metal ion in other components than a main component; a light source for projecting light into the non-linear optical crystal in an operation mode; and a refractive index recovery mechanism for carrying out a recovery operation for recovering a refractive index of said non-linear optical crystal as shifted overtime due to light projected into the non-linear optical crystal in the operation mode with an applied external energy into the non-linear optical crystal in a non-operation mode in which light is not injected to the non-linear optical crystal.

Abstract: A wavelength converting element which does not generate crystal destruction and output saturation of a second harmonic due to a third harmonic generated inside the element is provided. The wavelength converting element receives a fundamental wave which is light having a wavelength (lambda), outputs the second harmonic which is light having a wavelength (lambda/2), and has a crystal including at least one element selected from a group composed of Sc, Y, La, Ce, Pr, Eu, Gd, Ho, Yb, and Lu as an additive.

Abstract: A high-efficiency white-light-emitting device that includes a polariton light emitter that emits UV or blue light to a down-converting material that converts the polariton emissions to white light. The polariton light emitter includes an active region situated within a resonant optical cavity formed on a substrate. The down-converting material can comprise a luminophoric phosphor or other material. The polariton light and down-converting material can be arranged in a single apparatus to provide a white-light-emitting device that can be used for lighting and instrumentation. The device can also be configured for high-frequency modulation to provide optical signals for communications and control systems.

Abstract: Particular embodiments of the present disclosure bring an SHG crystal, or other type of wavelength conversion device, into close proximity with a laser source to eliminate the need for coupling optics, reduce the number of package components, and reduce package volume. According to one embodiment of the present disclosure, an optical package is provided comprising a laser source subassembly comprising a laser base and a wavelength conversion device subassembly comprising a converter base. The bonding interface of the laser base is bonded the complementary bonding interface of the converter base such that the laser output face can be proximity-coupled to the converter input face at an predetermined interfacial spacing x. Additional embodiments are disclosed and claimed.

Abstract: Particular embodiments of the present disclosure bring an SHG crystal, or other type of wavelength conversion device, into close proximity with a laser source to eliminate the need for coupling optics, reduce the number of package components, and reduce package volume. According to one embodiment of the present disclosure, an optical package is provided comprising a laser source and a wavelength conversion device. The laser source is positioned such that the output face of the laser source is proximity-coupled to a waveguide portion of the input face of the wavelength conversion device. The input face of the wavelength conversion device comprises an ?-cut facet and ?-cut facet. The ?-cut facet of the input face is oriented at a horizontal angle ?, relative to the waveguide of the wavelength conversion device to permit proximity coupling of the output face of the laser source and the input face of the wavelength conversion device.

Abstract: A light source device includes: a first light source unit and a second light source unit emitting light; and a wavelength conversion element converting wavelengths of lights emitted from the first light source unit and from the second light source unit. Chief ray of light emitted from the first light source unit and transmitted through the wavelength conversion element is not parallel with chief ray of light emitted from the second light source unit and transmitted through the wavelength conversion element.

Abstract: The present invention relates to a green laser generation device which can be applied to a cellular phone, and more particularly to a green laser generation device which is ultra compact in size having volume of 1 cc or less, despite having a built-in thermo electric cooler, and has sufficient output power, despite having low power consumption, and a portable electronic machine having a laser projection display using the said device. The present invention provides a green laser generation device comprising an LD pump constituted by a photo diode; a fundamental generator generating infrared light laser according to the driving of the LD pump; a second harmonic generator generating green light using the generated infrared light laser; a polarization maintenance unit inserted between the fundamental generator and the second harmonic generator to maintain the polarization of the laser; and a temperature controller controlling an internal temperature of the green laser generation device.

Abstract: An optical package includes a semiconductor laser, a wavelength conversion device and a MEMS-actuated mirror oriented on a base module to form a folded optical pathway between an output of the semiconductor laser and an input of the wavelength conversion device. An optical assembly is located in a mechanical positioning device and the mechanical positioning device is disposed on the base module along the optical pathway such that the beam of the semiconductor laser passes through the optical assembly, is reflected by the MEMS-actuated mirror back through the optical assembly and into the waveguide portion of the wavelength conversion device. The MEMS-actuated mirror is operable to scan the beam of the semiconductor laser over the input of the wavelength conversion device. The optical assembly may be adjusted along the optical pathway with the mechanical positioning device to focus the beam into the waveguide portion of the wavelength conversion device.

Abstract: The present invention comprises: a laser light source 101 operable to output a laser light; an optical component 114 operable to couple, to an optical fiber 126, the laser light outputted from the laser light source 101; an actuator 118 operable to hold the optical component 114; a photoreceiver 503 operable to monitor the laser light outputted from the optical fiber; and a control device 117 operable to drive the actuator 118 in accordance with a result of the monitoring by the photoreceiver 503, thereby controlling a position of the optical component 114.

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: All-optical quasi-phase matching (QPM) uses a train of counterpropagating pulses to enhance high-order harmonic generation (HHG) in a hollow waveguide. A pump pulse enters one end of the waveguide, and causes HHG in the waveguide. The counterpropagation pulses enter the other end of the waveguide and interact with the pump pulses to cause QPM within the waveguide, enhancing the HHG.

Abstract: A laser beam source device includes: a light source which emits light having fundamental wavelength; a wavelength conversion element which converts the light having fundamental wavelength into light having conversion wavelength; a resonance element which transmits first light converted into the conversion wavelength light and reflects light not converted; an optical path conversion element which releases second light contained in the light reflected by the resonance element and converted into the conversion wavelength light in the same direction as the direction of the first light, and releases the light not converted toward the light source; and a supporting member. The resonance element is disposed in such a position that one end surface of the resonance element on the second light side is shifted to the supporting member from one end surface of the wavelength conversion element on the second light side.

Abstract: Emissive quantum photonic imagers comprised of a spatial array of digitally addressable multicolor pixels. Each pixel is a vertical stack of multiple semiconductor laser diodes, each of which can generate laser light of a different color. Within each multicolor pixel, the light generated from the stack of diodes is emitted perpendicular to the plane of the imager device via a plurality of vertical waveguides that are coupled to the optical confinement regions of each of the multiple laser diodes comprising the imager device. Each of the laser diodes comprising a single pixel is individually addressable, enabling each pixel to simultaneously emit any combination of the colors associated with the laser diodes at any required on/off duty cycle for each color. Each individual multicolor pixel can simultaneously emit the required colors and brightness values by controlling the on/off duty cycles of their respective laser diodes.

Abstract: The output of a mode-locked solid-state NIR laser having a pulse duration less than 50 picoseconds at a pulse-repetition frequency is frequency doubled in a nonlinear crystal to provide green radiation. The green radiation is type-I frequency doubled in a BBO crystal to provide UV radiation. The green radiation is focused into an elliptical spot in the BBO crystal with the major axis of the spot in the walk-off plane of the crystal. The length of the crystal is chosen to be much less than the Rayleigh range of the green radiation in the walk-off plane of the BBO crystal.

Abstract: A fiber laser and an optical device for controlling polarization and outputting single polarized light are provided in a simple structure. The fiber laser includes a solid-state laser fiber (3) doped with a rare earth element, a pump light source (1) for exciting the solid-state laser fiber, a reflective element (2) having wavelength dependency, and a wavelength conversion element (4) arranged at the output side of the solid-state laser fiber away from the reflective element at a specified distance along the solid-state laser fiber, in which an end face of the wavelength conversion element (4) is inclined to an optical axis.

Abstract: A method and circuit is disclosed for a laser system wherein the power of the laser signal is kept at a constant near optimum value and a portion of an frequency doubled output signal is monitored and detected so that noise within the frequency doubled output signal can be minimized. A feedback signal is used to dither the temperature of a frequency doubled crystal so as to minimize the noise in the frequency doubled output signal.

Abstract: A method for aligning an optical package including a semiconductor laser operable to emit an output beam having a first wavelength, a wavelength conversion device operable to convert the output beam to a second wavelength and adaptive optics configured to optically couple the output beam into a waveguide portion of an input facet of the wavelength conversion device includes measuring a power of light having a first wavelength emitted by or scattered from the wavelength conversion device as the output beam is scanned over the input facet of the wavelength conversion device along a first scanning axis. A power of light emitted from the wavelength conversion device is then measured as the output beam is scanned over the input facet along a second scanning axis. A position of the second scanning axis relative to an edge of the wavelength conversion device is based on the measured power of light having the first wavelength.

Abstract: A method of operating a frequency-converted laser source is provided. According to the method, the gain section of a laser diode is driven such that the pulse repetition frequency ?P of the laser source is less than but sufficiently close to a mathematical reciprocal of the round-trip light flight time tF of the external laser cavity of the laser source, or an integer multiple thereof. In this manner, respective self-seeding laser pulses generated from the pulsed optical pump signal reach the gain section of the laser diode during buildup of successive optical pump signal pulses. Additional embodiments are disclosed and claimed.

Abstract: A method of operating a laser projection system is provided. The projection system comprises an external cavity laser, an optical intensity monitor, laser projection optics, and a controller. The external cavity laser comprises a laser diode, an intra-cavity wavelength conversion device, and a wavelength selective element. According to the method, the position of the wavelength selective element is adjusted relative to an optical axis Z of the external cavity laser to optimize output intensity. Specifically, the position of the wavelength selective element is adjusted by (i) tilting the wavelength selective element about its wavelength selective axis Y to reflect a wavelength of interest along an optimum path in an XZ plane of the external laser cavity and (ii) tipping the wavelength selective element about its wavelength insensitive axis X to reflect the wavelength of interest along an optimum path in a YZ plane of the external laser cavity. Additional embodiments are disclosed and claimed.

Abstract: A laser source device includes: a plurality of lasers; wavelength converting elements that convert wavelengths of a plurality of light beams emitted from the plurality of lasers; a temperature sensor that detects the temperatures of the wavelength converting elements; and a temperature controlling unit that controls the temperatures of the wavelength converting elements on the basis of an output of the temperature sensor.

Abstract: A wavelength conversion element includes a second harmonic wave generating element provided with an entrance surface and an emission surface, a function of converting an incident fundamental wave into a second harmonic wave with a different wavelength and emitting the second harmonic wave, and a cyclic polarization inversion structure configured so as to be able to match a phase of the second harmonic wave in a pseudo manner, and a first wavelength dispersive optical element disposed on the entrance surface side of the second harmonic wave generating element, having a first diffraction surface for diffracting an incident light beam with a diffraction angle increasing in accordance with a wavelength of an incident light beam to disperse the incident light beam by the wavelength of the incident light beam, and for emitting the light beam dispersed in the first diffraction surface towards the second harmonic wave generating element.

Abstract: A laser generator includes a generation means for pumping by a pumping light source (7) a pumping medium (3) to generate a fundamental-wave laser beam, an output sensor (6) for measuring average output power or pulse energy of the fundamental-wave laser beam, a wavelength-conversion element (5), arranged on an optical path for the fundamental-wave laser beam, for converting the fundamental-wave laser beam into its higher-harmonic-wave laser beam, and a controller (9) for memorizing a determination value set to a value lower than a breakage threshold for average output power or pulse energy of the laser beam converted by the wavelength-conversion element (5), and for, when the measurement value becomes not lower than the determination value, controlling the output power of the fundamental-wave laser beam to be a value lower than the breakage threshold; thereby, the beam intensity through the wavelength-conversion element (5) never exceeds the breakage threshold, and thus breakage of the wavelength-conversion e

Abstract: A method is provided for controlling a DBR laser diode wherein front and rear DBR section heating elements are controlled such that the reflectivity of the rear grating portion of the DBR section is lower than the reflectivity of the front grating portion of the DBR section. In this manner, lasing mode selection is dominated by the front grating portion and the front DBR section heating element can be controlled for wavelength tuning. In addition, the rear DBR section heating element can be controlled to narrow the spectral bandwidth of the DBR reflection spectra. Additional embodiments are disclosed and claimed.

Abstract: A light source device includes a semiconductor laser, and a drive circuit supplying the semiconductor laser with a pulsed drive current, and in the semiconductor laser, a laser emitting element and a free wheel diode are formed on the same substrate, and a cathode of the free wheel diode is connected to a current input terminal of the laser emitting element, and an anode of the free wheel diode is connected to a current output terminal of the laser emitting element.

Abstract: A method and apparatus for modulating a particular light source used for laser display are provided. The apparatus includes a digital modulator digitally modulating light output from a semiconductor laser to a frequency higher than a repetition frequency required for laser image display; and a pixel brightness adjustor inserting at least one high-speed pulse into a period of the modulated output light, which is required for a single pixel, and adjusting a brightness of the pixel by adjusting the number of the inserted high-speed pulses.

Abstract: A method of controlling a frequency-converted laser source is provided where the laser source comprises a laser cavity, an external optical feedback component, a wavelength selective component, and a wavelength conversion device and the method comprises driving a phase section of the laser cavity with a phase control signal that comprises a modulation component having a modulation amplitude ?MOD that is sufficient to shift the available cavity modes in the spectral domain such that lasing at several different cavity modes sequentially is established as the phase control signal is modulated.

Abstract: To make it possible to use a type I nonlinear optical crystal or a quasi phase matching element as a third harmonic generation crystal there is provided a semiconductor laser, a solid state laser medium that outputs a fundamental wave, a second harmonic generation crystal that outputs a second harmonic wave from the fundamental wave, and a third harmonic generation crystal that outputs a third harmonic wave from the fundamental wave and the second harmonic wave. A quasi phase matching elements is utilized as the second harmonic generation crystal. It is possible to use a type I nonlinear optical crystal or a quasi phase matching element as the third harmonic generation crystal.

Abstract: A wavelength converter comprising an arsenic sulfide (As—S) chalcogenide glass fiber coupled to an optical parametric oscillator (OPO) crystal and a laser system using an OPO crystal coupled to an As—S fiber are provided. The OPO receives pump laser radiation from a pump laser and emits laser radiation at a wavelength that is longer than the pump laser radiation. The laser radiation that is emitted from the OPO is input into the As—S fiber, which in turn converts the input wavelength from the OPO to a desired wavelength, for example, a wavelength beyond about 4.4 ?m. In an exemplary embodiment, the OPO comprises a periodically poled lithium niobate (PPLN) crystal. The As—S fiber can include any suitable type of optical fiber, such as a conventional core clad fiber, a photonic crystal fiber, or a microstructured fiber.

Abstract: Lasers configured for intracavity harmonic generation of second and higher order harmonic laser beam energy include mode-matching optics, such as a curved mirror, for recycling an unused portion of an intermediate harmonic laser beam energy (e.g., second harmonic laser beam energy) to improve higher order harmonic laser beam energy generation efficiency (e.g., third or higher order harmonic laser beam energy generation efficiency) without sacrificing beam quality of the higher order harmonic laser beam energy. The curved mirror may be positioned out of a resonant laser cavity of the laser. A radius of curvature and a position of the curved mirror are selected so that a beam radius and a beam divergence of the recycled second harmonic laser beam energy are essentially the same as a beam radius and a beam divergence of incoming second harmonic laser beam energy everywhere along a beam path of the incoming second harmonic laser beam.

Abstract: Methods, apparatus and systems for an up-converter resonant cavity light emitting diode device includes a semiconductor light source, an up-converter to form the light emitter with up-converting materials and an electrical source coupled with the semiconductor light source for providing electrical energy to the semiconductor light source to provide a desired wavelength emitted light. The semiconductor light source is a resonant cavity light emitting diode or laser that emits an approximately 975 nm wavelength to provide electrical and optical confinement to the semiconductor light source to form a resonant cavity up-converting light emitting diode (UC/RCLED). Rows and columns of electrodes provide active matrix addressing of plural sets of UC/RCLEDs for display devices.

Abstract: A laser device includes: an amplifying medium (1, 7) adapted to generate a fundamental wavelength laser beam (13); a birefringent non-linear medium (3, 20, 20) for doubling the fundamental wavelength laser beam to generate a harmonic wavelength laser beam (14); a polarizing medium (1b, 5, 6, 2, 8, 9, 16, 20) for selecting a fundamental wavelength laser beam polarization, the polarizing medium being such that the fundamental wave at its output remains parallel to the fundamental wave at its input. The invention is characterized in that the polarizing medium (1b, 5, 6, 2, 8, 9, 16, 20) has an output side (2b) perpendicular to the fundamental wave exiting the polarizing medium. The amplifying medium, the birefringent non-linear medium are mutually integral so as to constitute a monolithic resonant cavity.

Abstract: A semiconductor laser light source 10 emits a laser beam for pumping. An optical resonator 2 includes a solid laser crystal 15 to be excited by the incident of a laser beam to oscillate a fundamental wave 20 and a pair of fundamental wave reflective coats 14, 16 arranged at the opposite sides of the solid laser crystal 15. A wavelength conversion element 18 converts the fundamental wave 20 into a plurality of harmonics 21, 22. The wavelength conversion element 18 is so arranged in the optical resonator 2 that the optical axis of at least one of the plurality of harmonics 21, 22 generated in the optical resonator 2 is made different from that of the fundamental wave 20 and the at least one harmonic 22 whose optical axis is made different is output substantially in the same direction as the other harmonic 21. By this construction, it is possible to stabilize a harmonic output and utilize a plurality of harmonics without increasing the number of parts.

Abstract: A system is provided for providing high power, wavelength tunable, laser radiation, the system comprising: a plurality of seeder sources, each the source of the plurality having a different seeder wavelength; a Ytterbium doped amplifier chain, receiving radiation from the plurality of seeder sources and at least one pump source; a second harmonic generator communicating with the Ytterbium doped amplifier chain, the second harmonic generator comprising converting radiation of the seeder wavelength into radiation of a second harmonic wavelength; and wherein the second harmonic generator comprises a crystal having a plurality of grating segments, wherein each grating segment converts radiation of a different wavelength.

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 is disclosed, which is suitable for efficient generation of continuous-wave laser light having a wavelength of about 400 nm or less. The short-wavelength light is generated by first frequency-doubling a fundamental wave, and then sum-frequency mixing the frequency-doubled wave and the fundamental wave. The non-linear interactions are effected by means of quasi-phasematching structures inside a resonant cavity where the fundamental wave is circulating. The sum-frequency mixing is effected using second or higher order quasi-phasematching, which allows for wider domains to be inverted for the quasi-phasematching structure compared to first order quasi-phasematching. Preferably, the sum-frequency mixing is effected using periodically poled stoichiometric lithium tantalate (PPSLT) for second or third order quasi-phasematching.

Abstract: A device for producing a polychromatic light including an optical pump that delivers a first radiation at a first wavelength; a light guide; and a selective injector that injects the radiation into the guide, the guide being arranged to generate a harmonic corresponding to the selected injector and provide a polychromatic light at an outlet, by non-linear excitation of the first radiation and the harmonic.

Abstract: The invention is a single-crystal passively mode-locked semiconductor vertical-external-cavity surface-emitting laser (VECSEL). The device can be a single emitter or an array of emitters. The VECSEL structure is grown on a GaAs, InP or GaSb substrate. The device consists of an active region with a number of quantum wells (QW) made of GaInAs, GaInAsP, GaInNAs, GaInNAsSb, AlGaAs or GaAsP. The fundamental lasing wavelength is chosen by the gain material. The gain region is sandwiched between the bottom reflector with reflectivity close to 100% and a partial reflector. A semiconductor spacer layer made of e.g. GaAs or AlGaAs is separating the gain region and a semiconductor saturable absorber. The saturable absorber consists of one or more quantum wells made of GaInAs, GaInAsP, GaInNAs, GaInNAsSb, AlGaAs or GaAsP and a second partial reflector.

Abstract: A light source device includes: a laser light source emitting a laser beam of a prescribed wavelength; a nonlinear optical element, disposed facing a light emergence surface of the laser light sources which converts an emission wavelength of the laser beam emitted from the laser light source and causes the laser beam to emerge; a volume phase grating, disposed facing an emergence surface of the laser beam of the converted wavelength converted by the nonlinear optical element, which has formed in an interior thereof a Bragg grating structure which selectively reflects a laser beam of an emission wavelength; and a first dielectric multilayer, provided on a light emergence surface of the volume phase gratings which transmits the laser beam of the converted wavelength and reflects the laser beam of the emission wavelength.