Abstract: It is aimed to suppress a local increase of an energy density per unit time in a nonlinear crystal. A fundamental wave emitted from a fundamental wave laser light source is condensed by a condenser lens and incident on a nonlinear crystal 11 having a poled structure. By displacing a focus position of a fundamental wave 50 by means of a scanning mirror 21, a local increase of the energy density per unit time in the nonlinear crystal 11 is suppressed.

Abstract: A wavelength converter including a fiber provided with a laser active substance and formed with first and second fiber gratings embedded in the fiber, a laser light source that allows pumping light to be incident on the fiber, a laser resonator formed by optically connecting the fiber and the laser light source, and a wavelength conversion element that converts the fundamental wave of a laser beam emitted from the laser resonator into a higher harmonic wave. The fiber absorbs a part of an output of the fundamental wave or the pumping light, and heats the second fiber grating. The temperature of the second fiber grating is adjusted in accordance with an output of the higher harmonic wave outputted from the wavelength conversion element.

Abstract: A GaN-based semiconductor laser (1) emits first laser light of a single polarization and having a first wavelength. An optical resonator (30) includes a solid-state laser medium which is excited by incidence of the laser light and which oscillates second laser light having a second wavelength different from the first wavelength. A polarization switch (6) switches over at least one of polarization directions of the first laser light and the second laser light to thereby change the wavelength of laser light to be emitted from the optical resonator (30) or the intensity ratio between a plurality of laser light to be emitted from the optical resonator (30). With the above arrangement, a plurality of laser light can be used effectively.

Abstract: A holographic optical information playback apparatus for playing information that is recorded on a recording medium in a form of interference fringes is provided with a two-dimensional photoreceptor array which receives a two-dimensional array of light spots that is diffracted at the recording medium due to application of reference light onto the medium, and outputs a playback signal including information recorded on the recording medium. The two-dimensional photoreceptor array has a photoreceptor section in which plural photoreceptor cells for detecting the intensities of received lights are arranged so that a photoreceptive area corresponding to the light spot array is formed, and assigns plural photoreceptor cells are assigned to each light spot in the light spot array according to the irradiation position of the light spot array, whereby the light intensity of one light sport is detected using the output signals from the plural photoreceptor cells.

Abstract: A wavelength converter is provided with an infrared light source (1) for emitting a fundamental wave having a wavelength of 2000 nm or shorter, a wavelength conversion element (3) composed of a nonlinear optical crystal having a periodical polarization reversal structure and adapted to convert a fundamental wave emitted from the infrared light source (1) into a harmonic wave, and a heater (4) for heating the wavelength conversion element (3). The period of the polarization reversal structure is designed so that a quasi phase matching temperature of the fundamental wave and the harmonic wave is 40° C. or higher. The heater (4) heats the wavelength conversion element (3) to a temperature at which quasi phase matching is established, and the nonlinear optical crystal contains a lithium niobate or lithium tantalate including at least any one of additives Mg, In, Zn and Sc as a main component. Thus, optical damage can be suppressed and visible light absorption attributed to ultraviolet light can be reduced.

Abstract: A laser light source having a semiconductor laser (102) for outputting pump light, and a laser resonator wherein a solid laser crystal (104) and a non-linear optical crystal (103) are connected by optical contact and a reflection coat (106) and a reflection coat (105) are on the opposed facets of the respective crystals. GdVO4 is the solid laser crystal (104) while LiNbO3 is the non-linear optical crystal (103), and the crystal axis of the solid laser crystal (104) is inclined with respect to the z axis of the non-linear optical crystal (103) within the z-x plane of the non-linear optical crystal (103). The thermal expansion coefficients of the solid laser crystal and of the non-linear optical crystal can be approximated to each other, thereby preventing separation of the bonded laser crystal and non-linear optical crystal due to different thermal expansion coefficients when heat is generated during laser oscillation, which stops laser oscillation.

Abstract: A short wavelength light source includes a wavelength conversion element having an incident surface, on which a fundamental wave is incident, and an output surface, from which a harmonic wave is outputted, the wavelength conversion element being provided for converting the fundamental wave into the harmonic wave; and a holder for holding said wavelength conversion element, wherein the wavelength conversion element has a specific region on the light output side, which is arranged so as to suppress variations in phase matching condition between the fundamental wave and the harmonic wave resulting from heat generated by absorbing the harmonic wave during a wavelength conversion.

Abstract: A wavelength conversion element is provided with a substrate including a nonlinear optical single crystal having a periodically poled structure, the visible light transmittance of the substrate is 85% or higher when ultraviolet light is irradiated to the substrate, and laser light having an average output of 1 W or more is outputted by shortening the wavelength of laser light having a wavelength of 640 nm to 2000 nm. By improving visible light transmission characteristics when the ultraviolet light is irradiated in this way, the breakdown of crystal can be prevented and the stabilization of output characteristics at high output can be realized. As a result, the absorption of green light induced by ultraviolet light can also be suppressed, and the saturation of output and the breakdown of crystal can be avoided.

Abstract: A short wavelength light source of the present invention comprises a nonlinear crystal having a periodical polarization reversal structure. The polarization reversal structure of the nonlinear crystal is divided into a plurality of regions and the polarization reversal structure and the optical axis of the fundamental wave are inclined with different angles in the respective regions, so that higher harmonic generated is divided into a plurality of beams. By dividing the higher harmonic component into a plurality of beams, it is possible to reduce the power density of the higher harmonic and generate walk off in the fundamental wave and the higher harmonic, thereby to suppress generation of the sum frequency waves of the fundamental wave and the higher harmonic so as to enhance the tolerance to high output. Therefore, SFG generation is suppressed, and a high output power coherent light source is realized.

Abstract: According to the present invention, a laser light source comprises plural semiconductor lasers (2), a solid laser (4), a non-linear material (3) as a wavelength conversion element, a reflection coat (5) formed on one facet of the solid laser, and a reflection coat (6) formed on one facet of the non-linear material (3), and the solid laser and the wavelength conversion element are disposed between the both reflection coats to constitute a laser resonator, and plural pump parts (8) in the solid laser (4) which are pumped by the plural semiconductor lasers are separated from each other by 300 ?m or more. Thereby, interference between transverse modes of laser oscillation is avoided, thereby providing a high-power, stable, and compact solid laser light source with which a stable high output power can be obtained.

Abstract: A short wavelength light source is provided with a fundamental wave light source for generating a fundamental wave, and a plurality of wavelength conversion elements made of nonlinear optical crystals having periodic polarization-inversion structures and adapted to convert a part of the fundamental wave into a second harmonic, and the nonlinear optical crystals of the plurality of wavelength conversion elements are different in material or composition. By converting the fundamental wave from the fundamental wave light source by the plurality of wavelength conversion elements, the generation of a thermal lens effect caused by light absorption can be suppressed to improve a high output resistance.

Abstract: The present invention concerns a laser light source device capable of multiwavelength oscillation. This laser light source device is provided with a laser light source; a laser cavity including a fiber, a first fiber grating provided at a side of the fiber toward the laser light source and having a plurality of reflection peaks, and a second fiber grating provided at a light emission end of the fiber and having a plurality of reflection peaks: a wavelength converter for converting a fundamental wave emitted from the laser cavity into a harmonic wave; a reflection wavelength varying unit capable of shifting the reflection wavelengths of the reflection peaks of the second fiber grating; and a controller for controlling phase matching conditions of the wavelength converter. Intervals between adjacent reflection peaks of the first fiber grating are different from those between adjacent reflection peaks of the second fiber grating.

Abstract: A solid-state laser apparatus includes: a semiconductor laser light source for emitting laser light; an optical resonator having a solid-state laser medium to be excited by incidence of the laser light to oscillate fundamental laser light, and a mirror; and a quasi phase matching wavelength converting element, disposed in the optical resonator, for converting a wavelength of the fundamental laser light, wherein the quasi phase matching wavelength converting element is formed with a polarization inversion region having a predetermined cycle, and the length of the polarization inversion region in an optical axis direction is 1.0 mm or less.

Abstract: A wavelength conversion laser is provided with a pair of fundamental wave reflecting surfaces for reflecting a fundamental wave to define a plurality of fundamental wave paths passing a wavelength conversion element at different angles, and a control unit for controlling wavelength conversion efficiencies so that the wavelength conversion efficiency on a specific one of the plurality of fundamental wave paths extending in different directions between the pair of fundamental wave reflecting surfaces is highest.

Abstract: A display for illuminating a liquid crystal display panel with laser light of uniform light quantity distribution, and an illuminator for irradiating with laser light of uniform light quantity distribution are provided. The display includes a liquid crystal display panel 204, laser light sources 205, 206, 207 emitting laser light having wavelengths of green, red, and blue colors, a waveguide plate 201 arranged at the back side of the liquid crystal display panel 204 and performing multiple reflection of laser light, and a diffusion plate 202 arranged at the back side of the waveguide plate 201, diffusing laser light propagating in the waveguide plate 201 and emitting the light toward liquid crystal display panel 204.

Abstract: There is provided a light source device which can miniaturize a two-dimensional image display device as small as possible. The light source device is provided with three coherent light sources (11a), (11b), and (11c) corresponding to red, blue, and green; prisms (12a) and (12c) for reflecting lights emitted from the coherent light sources (11a) and (11c); and a diffraction part (20) comprising a single volume hologram on which plural gratings are multiply-formed, which gratings diffract the light emitted from the coherent light source (11b), and the lights that are emitted from the coherent light sources (11a) and (11c) and reflected by the prisms (12a) and (12b) so that these lights propagate in the same optical path.

Abstract: A wavelength conversion apparatus capable of stably providing high output harmonic laser light is provided. The wavelength conversion apparatus comprises an end pump fiber laser 3 containing a laser activating substance, and including a reflecting surface at one end thereof and a fiber grating in the vicinity of the reflecting surface; an excitation laser light source 1 for outputting excitation laser light; an excitation laser light introduction section 4 for introducing the excitation laser light from the excitation laser light source to the fiber laser; a wavelength conversion element 5 for converting a fundamental wave generated by the fiber laser to a harmonic; and a rear reflecting surface 6 located outside the fiber laser and forming a laser cavity together with the fiber grating.

Abstract: Upon obtaining green light as wavelength converted light by causing infrared light to be incident on a wavelength conversion element, the absorption of the green light occurs due to the generation of ultraviolet light as sum-frequency light of the infrared light and the green light in the wavelength conversion element and the destruction of a crystal composing the wavelength conversion element occurs due to heat generated at this time. In a laser wavelength converter of the present invention, a condensed position of the infrared light in the wavelength conversion element is deviated from a position assumed to be optimal when the influence of the generated heat is ignored. Consequently, crystal destruction is suppressed, a high-efficiency wavelength conversion is enabled and high-output wavelength converted light exceeding several watts, which was difficult to attain in conventional wavelength conversion elements, is attained.

Abstract: A wavelength conversion module includes: a first fundamental wave propagation optical fiber for propagating a fundamental wave emitted from a laser light source; a first wavelength conversion element, optically connected to the first fundamental wave propagation optical fiber, for converting the fundamental wave emitted from the first fundamental wave propagation optical fiber into a harmonic wave; and a first harmonic propagation optical fiber, optically connected to the first wavelength conversion element, for propagating the harmonic wave emitted from the first wavelength conversion element, wherein the core diameter of the first harmonic propagation optical fiber is 0.5 to 0.9 times as large as the core diameter of first fundamental wave propagation optical fiber.

Abstract: A semiconductor laser device and an image display device that efficiently release a heat from stripe active regions, and operated at a low-consumption current and a low-consumption electric power. A semiconductor laser element includes stripe active regions for emitting laser beams. On a base block, there are formed wirings electrically connected to stripe laser electrodes of the semiconductor laser element, respectively. The stripe laser electrodes corresponding to the stripe active regions are formed in proximity to a first surface of the semiconductor laser element, close to the active regions. An electric current is supplied to the active regions from connecting portions between each of the laser electrodes and the wirings.