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 surface illumination apparatus includes: a light source; an end-surface light-guide portion which guides light emitted from the light source in a long-side direction thereof and generates emitted light in a short-side direction thereof; and a light guide plate which allows the emitted light to be incident upon an end-surface portion thereof and emits the incident light from one main-surface portion thereof. The end-surface light-guide portion includes a plurality of polarization control portions arranged in the long-side direction; the plurality of polarization control portions each has a half-wave plate and a polarizing prism; the end-surface light-guide portion emits the emitted light in the form of either of S-polarized light and P-polarized light, using the plurality of polarization control portions; and the light guide plate emits, as output light, either of S-polarized light and P-polarized light from the one main-surface portion.

Abstract: An image display apparatus is provided with a laser light source, a spatial light modulation device for modulating the laser light emitted from the laser light source, a display surface for displaying the modulated light, an optical pixel aperture enlarging member for distributing the luminance of the laser light while introducing the laser light to apertures of pixels of the spatial light modulation device; and a display pixel aperture enlarging portion for optically enlarging the modulated light by the apertures of the pixels of the spatial light modulation device corresponding to pixels of an image to be displayed on the display surface.

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.

Abstract: Miniaturization is realized and high-output lights are obtained by optimizing the arrangement of a laser light source unit and a homogenizer. A laser light source unit 1 has a light emission region for emitting an elliptical laser light. A focusing lens unit 2 focuses the laser light emitted from the laser light source unit 1. A rod integrator 4 has a rectangular incident surface on luminous flux focused by the focusing lens unit 2. A spatial light modulation element 7 modulates the laser light emitted from the rod integrator 4. A projection lens 8 projects the laser light modulated by the spatial light modulation element 7. The incident surface of the rod integrator 4 has a rectangular shape, and the laser light source unit 1 is arranged such that a longer axis direction of the light emission region and a longer side direction of the incident surface of the rod integrator are parallel.

Abstract: A wavelength converting apparatus comprising: a laser resonator; a first wavelength converting element that converts a fundamental wave outputted from the laser resonator into a harmonic wave; a first temperature control element that controls the temperature of the first wavelength converting element; a second wavelength converting element that converts a fundamental wave outputted from the first wavelength converting element into a harmonic wave; a second temperature control element that controls the temperature of the second wavelength converting element; a first detecting portion that detects an output of a harmonic wave outputted from the first wavelength converting element; a second detecting portion that detects an output of a harmonic wave outputted from the second wavelength converting element; and a controller that manages temperature control of the first wavelength converting element by the first temperature control element, temperature control of the second wavelength converting element by the seco

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: For performing hologram recording or reproduction, an oscillation wavelength half value width ?? of a coherent light source satisfies a relationship of ??<?2/(S×2 sin ?), where a substantial hologram size is S, a substantial cross angle between reference light and signal light is ?, and the oscillation wavelength of the coherent light source is ?. Even when stray light is generated, the coherent light source can suppress generation of an unnecessary interference fringe due to the stray light, and stably record and reproduce holograms.

Abstract: A multipurpose projector 100 is provided with a fiber bundle 6 including a plurality of cores fixedly arranged on an input plane and an output plane, laser beam sources 1r, 1g and 1b for emitting laser beams having directivities, an optical guide unit 2 to 5 for modulating the laser beams emitted from the laser beam sources 1r, 1g and 1b and guiding the modulated laser beams to the input plane of the fiber bundle 6, a projection lens 8 for enlarging and projecting the laser beams emerging from the output plane of the fiber bundle 6 to a display space 12, and a projection angle adjusting mechanism 7 disposed on the side of the output plane of the fiber bundle 6 for adjusting projection angles of the laser beams projected from the projection lens 8. Thus, the projector can have its projection space freely operated and enlarged to extend its application not only to image display, but also to illumination and decoration with colored light.

Abstract: The present invention provides a planar lighting device (1) including: a laser light source (12) which emits a linearly-polarized laser beam; an optical member (13) which receives the laser beam, then parallelize the laser beam, and emits the parallelized laser beam; and a first plate-shaped light guide (20) which receives the parallelized laser beam from an end face portion (20d) and emits the parallelized laser beam from a first major surface (20b). The first light guide includes an optical element (20a) which receives the linearly-polarized parallelized laser beam propagated through the first light guide and emits at least a part of the linearly-polarized parallelized laser beam in a direction substantially vertical to the first major surface. The present invention also provides a liquid crystal display device (3) using the planar lighting device (1) as a backlight lighting device.

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 planar lighting device that applies light having high luminance with good monochromatic characteristics, and a liquid crystal display device using the same are provided. The planar lighting device (11) is provided with: a laser light source (12) that emits laser light beams of red, green and blue colors; at least one optical wave guide unit (14) that is placed in a plane state and is optically connected to the laser light source to propagate the laser light beams emitted from the laser light source; a planar light guide plate (15) that is arranged on a surface side of the optical wave guide unit, spreads the laser light beams propagating through the optical wave guide unit, and outputs the laser light beams from one of principal surfaces (21); and a plurality of light taking out units (19) that are arranged on the other principal surface of the light guide plate, and guide the laser light beams propagating through the optical wave guide unit to the light guide plate.

Abstract: A projector has: light source (1R, 1G, 1B); a light modulation unit (6) that modulates a light emitted from the light source based on image signals; a display control unit (41) that outputs the image signals including main cyclic image signals to the light modulation unit, and controls the display thereof; a projection unit (7) that projects the image based on the light modulated by the light modulation unit; and an imaging unit (40) that captures an image to be displayed based on the light projected from the projection unit, and the display control unit inserts a correction image signal for projecting a correction image, which is visually recognized as a uniform white or gray screen when time integration is performed, between the cyclic main image signals.

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: It is aimed to provide an LCD backlight device and liquid crystal display that can suppress light quantity loss and ensure uniform brightness. An LCD backlight device 101 has a laser light source 1 that emits laser light, and a light guiding plate 3 that transforms the laser light from the laser light source 1 into linear laser light, and transforms the linear laser light into a planar laser light, and emits the planar laser light, and the light guiding plate 3 has a third side face 6 that transforms the linear laser light into the planar laser light by reflecting the linear laser light by a plurality of reflection surfaces that are formed along the entrance direction of the linear laser light.

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: Provided is a fiber cutting mechanism that prevents secondary utilization of a fiber laser light source incorporated in a device that uses a laser light. With a characteristic fiber cutting mechanism, when a laser device is separated from a laser light source application apparatus, at least a fiber 26 is cut in an specific area from a point within a fiber grating 29 to a connection point between the fiber grating 29 and the fiber 26 containing a laser activating substance (cutting position area (1)).

Abstract: An information display device (10) includes a light source (11), a light guide plate (13) to which light from the light source (11) enters from a side surface and from which the light exits from one principal surface, and a liquid crystal panel (16) disposed adjacently to the light guide plate (13). Outside light is injected into the light guide plate (13) from an opposing surface opposing the one principal surface. The light guide plate (13) includes a light control mirror (19) electrically switchable to transmit light and to reflect light. At least one of the light from the light source (11) and the outside light exits from the one principal surface of the light guide plate (13). The light passes through the liquid crystal panel (16) and a character or an image is displayed.