Abstract: A surface illuminator has a uniform luminance over a large area by using a laser light source, has a wide color reproduction range, and is capable of suppressing a speckle noise. A liquid crystal display uses such a surface illuminator. The surface illuminator includes the laser light source that emits a laser beam; a beam scan section that deflects and scans the laser beam; and a first plate-shaped light guide that causes the laser beam deflected and scanned by the beam scan section to be incident from an end face portion and causes the incident laser beam to emit from a first major surface. Further, the liquid crystal display includes a liquid crystal display panel and the surface illuminator, wherein the surface illuminator is used as a backlight illuminator that lights the liquid crystal display panel from the backside in this liquid crystal display.

Abstract: A projection type display apparatus is provided that is safe even when a person looks directly into a laser beam. A laser operation control unit sets the output power of at least one laser source so that intensity A (mW/mm2) of the laser beam on at least one spatial light modulation element satisfies relationship of A<686×B2 when numerical aperture B on image side of an illumination optics system is set.

Abstract: There is a problem that in the connection portion between a rare-earth-doped double clad fiber and a single mode fiber, pumping light leaks in a portion having the coating, and the fiber generates heat partially with this energy and deteriorates. Also, there is another problem that the output is limited as the oscillation wavelength becomes shorter. Accordingly, in a laser light source device formed by combining a fiber laser and a fiber amplifier, by using the residual pumping light in the fiber laser as the pumping light in the fiber amplifier, it is possible to enhance the reliability by preventing the fiber deterioration caused by the residual pumping light. Further, by amplifying the output in the fiber amplifier in the latter stage without any limitation on the pumping light output, it is possible to increase an output of the oscillation light.

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: Since the absorption of a fundamental wave by a fiber increases if it is tried to obtain a wavelength conversion light of watt-class high output, the fiber length needs to be shortened. However, since oscillation efficiency conversely decreases if the fiber length is shortened, it is difficult to obtain a high-output fundamental wave. Thus, by reflecting an excitation light incident on the fiber in the fiber, the excitation light is efficiently absorbed to amplify the fundamental wave with a high gain. Further, by shortening the fiber length, the absorption of the fundamental wave is also reduced to improve a fundamental wave output. Consequently, a wavelength converter capable of ensuring a stable high output up to watt-class is achieved.

Abstract: A two-dimensional image display device using a Yb-doped clad pump fiber which is a rare-earth-doped fiber as a laser activation substance, whereby a peak of a fluorescence spectrum can be significantly increased as compared with a case of using an oxide crystal, and a variation width of an oscillation wavelength can be increased. Further, since the rare-earth-doped fiber is used as a fiber amplifier without providing laser mirrors at both ends thereof, control for a resonator length, which has been required in a conventional device (wherein an oxide crystal is used as a laser medium), is dispensed with, and thereby high-speed wavelength control is achieved, resulting in reduction in speckle noise when it is mounted on a two-dimensional image display device.

Abstract: Provided is a printing apparatus for printing information on a printing area of an object to be printed by irradiating the object to be printed with a first laser beam. The printing apparatus includes a light source for outputting the first laser beam, a light collecting optical system for collecting the first laser beam to the printing area of the object to be printed, and a scanning unit for performing scanning with the first laser beam. The object to be printed contains moisture at least in the printing area, and a wavelength of the first laser beam is 350 nm or more and 550 nm or less.

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 compact liquid crystal display device is provided by connecting a plurality of liquid crystal display panel units each provided with a light guiding plate unit on a back side with a connection portion and supplying a laser light source via the connection portion. It includes a plurality of display portions formed of liquid crystal display panel units and light guiding plate units disposed in intimate contact with the back sides of the liquid crystal display panel units, a connection portion connecting a plurality of the display portions, and a laser light source. By supplying a laser beam emitted from the laser light source to the light guiding plate units via the connection portion, the display surfaces of the liquid crystal display panel units are illuminated by the laser beam.

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: 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: Since the absorption of a fundamental wave by a fiber increases if it is tried to obtain a wavelength conversion light of watt-class high output, the fiber length needs to be shortened. However, since oscillation efficiency conversely decreases if the fiber length is shortened, it is difficult to obtain a high-output fundamental wave. Thus, by reflecting an excitation light incident on the fiber in the fiber, the excitation light is efficiently absorbed to amplify the fundamental wave with a high gain. Further, by shortening the fiber length, the absorption of the fundamental wave is also reduced to improve a fundamental wave output. Consequently, a wavelength converter capable of ensuring a stable high output up to watt-class is achieved.

Abstract: An illumination light source is provided with a laser light source having a laser medium with a specified gain region, and a reflector having a narrow band reflection characteristic. A part of a laser light emitted from the laser light source is reflected and fed back by the reflector, so that an oscillation wavelength of the laser light source is fixed at a reflection wavelength. A peak of a gain region of the laser medium is shifted from the reflection wavelength by a change of an oscillation characteristic of the laser light source, so that the oscillation wavelength of the laser light source is changed from the reflection wavelength. Thus, an oscillation spectrum of the laser light source is spread to reduce speckle noise.

Abstract: An internal resonator type SHG light source includes a pump light source which emits a pump light; a solid-state laser which absorbs the pump light and which emits a fundamental wave; an output mirror provided so as to face the solid-state laser, which forms a resonator together with the solid-state laser; a wavelength conversion element provided in the resonator, which converts the fundamental wave into a harmonic wave; a detector which detects a temperature of the wavelength conversion element; and a rotating unit which changes an incident angle of the fundamental wave on the wavelength conversion element by rotating the wavelength conversion element, wherein the rotating unit rotates the wavelength conversion element according to the temperature of the wavelength conversion element as detected by the detector.

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: 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 wavelength conversion device includes a laser light source that emits a fundamental wave; a wavelength conversion element that converts the fundamental wave into a second harmonic wave; and an optical system including a wavelength selective mirror that reflects the fundamental wave transmitted through the wavelength conversion element without being converted into the second harmonic wave, while transmitting therethrough the second harmonic wave generated by wavelength conversion, wherein the optical system makes the fundamental wave transmitted through the wavelength conversion element without being converted into the second harmonic wave enter the wavelength conversion element again to be subjected to wavelength conversion once or more than once, while being focused by the wavelength selective mirror, and the conversion efficiency in at least one of the second stage and stages subsequent to the second stage is higher than the conversion efficiency in the first stage, where the conversion efficiency in each

Abstract: There is a problem that in the connection portion between a rare-earth-doped double clad fiber and a single mode fiber, pumping light leaks in a portion having the coating, and the fiber generates heat partially with this energy and deteriorates. Also, there is another problem that the output is limited as the oscillation wavelength becomes shorter. Accordingly, in a laser light source device formed by combining a fiber laser and a fiber amplifier, by using the residual pumping light in the fiber laser as the pumping light in the fiber amplifier, it is possible to enhance the reliability by preventing the fiber deterioration caused by the residual pumping light. Further, by amplifying the output in the fiber amplifier in the latter stage without any limitation on the pumping light output, it is possible to increase an output of the oscillation light.

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 light source device with high use efficiency is provided. By using a laser light source of a single polarization, uniformization of light quantity and uniformization of polarization are simultaneously realized, in a two-dimensional planar illumination utilizing reflection and collimating. Thus, it is possible to realize the two-dimensional planar illumination with polarization aligned, and therefore the use efficiency of light can be significantly improved, when combined with switching utilizing the polarization of a liquid crystal panel, etc.