Abstract: In a semiconductor laser element having a plurality of semiconductor layers formed on a substrate, a groove-form concave portion is formed on the surface of the substrate opposite to the surface having the semiconductor layers. The concave portion is filled with metal having a higher heat conductivity higher than the substrate. The semiconductor laser element achieves improved heat dissipation characteristics and high reliability even under high-output operation.

Abstract: In a semiconductor laser device including having an index-guided structure and oscillating in a fundamental transverse mode, a lower cladding layer, a lower optical waveguide layer, a quantum well layer, an upper optical waveguide layer, and a current confinement structure are formed in this order. The thickness of the upper optical waveguide layer is smaller than the thickness of the lower optical waveguide layer. In addition, the sum of the thicknesses of the upper and lower optical waveguide layers may be 0.5 micrometers or greater. Further, the distance between the bottom of the current confinement structure and the upper surface of the quantum well layer may be smaller than 0.25 micrometers.

Abstract: An optical recording method in which an effective recording sensitivity in the recording of image information on a photosensitive material is raised, whereby a productivity is enhanced owing to lowered energy (laser power) required for the recording or a heightened recording speed. An image is recorded by projecting a light beam onto the photosensitive material formed on a base material backing. The optical recording method includes the steps of: (a) successively outputting pulse light whose duty factor is at most 50%, from a light source; (b) modulating the pulse light output from the light source, in accordance with an image signal, and then projecting the modulated pulse light onto the photosensitive material; and (c) recording the image by causing the pulse light to scan the photosensitive material.

Abstract: In a semiconductor laser element having a plurality of semiconductor layers formed on a substrate, a groove-form concave portion is formed on the surface of the substrate opposite to the surface having the semiconductor layers. The concave portion is filled with metal having a higher heat conductivity higher than the substrate. The semiconductor laser element achieves improved heat dissipation characteristics and high reliability even under high-output operation.

Abstract: A semiconductor light emitting apparatus includes a semiconductor light emitting element which includes a stripe structure and an active layer made of an InGaN material, and emits first light without laser oscillation; an optical resonator; and a first wavelength selection unit which allows resonance, in the optical resonator, of second light having a selected wavelength included in the first light emitted by the semiconductor light emitting element. Alternatively, instead of the first wavelength selection unit, a second wavelength selection unit which allows output of only the above second light from the semiconductor light emitting apparatus may be provided. In this case, the semiconductor light emitting apparatus may further include an optical detector which detects intensity of the second light; and an output regularizing unit which drives the semiconductor light emitting element based on the detected intensity so as to regularize the intensity of the second light.

Abstract: A transmission apparatus comprises a plastic fiber, and a photodetector for detecting light, which has been propagated through the plastic fiber. The photodetector comprises a plurality of semiconductor light receiving devices, whose light receiving sensitivity wavelength regions are identical with one another, each of the semiconductor light receiving devices having a light receiving area smaller than a cross-sectional area of a core of the plastic fiber. The transmission apparatus is capable of achieving both a high light receiving efficiency and quick response characteristics.

Abstract: A high-output semiconductor laser element includes a plurality of laser structures which are superposed on a substrate one on another with a P+N+-tunnel junction intervening between each pair of the laser structures. Each of the laser structures includes at least one active layer interposed between a P-type clad layer and a N-type clad layer. The active region of each of the laser structures is not smaller than 10 &mgr;m and not larger than 80 &mgr;m in width. The distance h between the active layers which are most distant from each other in the active layers of the laser structures is not larger than the width W of the active region which is the widest in the laser structures. The width of said semiconductor laser element is not smaller than W+2h.

Abstract: In a semiconductor laser device, an optical guide region includes an active layer and first and second optical waveguide layers respectively formed above and under the active layer, and first and second cladding layers are respectively formed above and under the optical guide region. Each of the first and second cladding layers includes at least one AlGaN layer. The thickness tg (nm) of the optical guide region and the thicknesses tc1 and tc2 of the first and second cladding layers satisfy a condition that −0.25 tg+500≦tc≦500 and 400≦tg when tg≦1600, and 100≦tc≦500 when tg>1600, where tc (nm) represents each of the thicknesses tc1 and tc2.

Abstract: Light, which has been produced by a semiconductor device and has wavelengths falling within the range of 630 nm to 680 nm, is propagated through a plastic fiber provided with a core containing a polymethyl methacrylate as a principal constituent. The temperature of the semiconductor device is adjusted by a temperature adjusting system comprising a heater for heating the semiconductor device, a temperature detector for detecting the temperature of the semiconductor device and feeding out a temperature detection signal, and a control circuit for controlling actuation of the heater in accordance with the temperature detection signal in order to set the temperature of the semiconductor device at a predetermined target value that is lower than the highest temperature assumed to occur under an environment, in which the semiconductor device is located.

Abstract: In an image exposing apparatus and an image exposing method, a deterioration of an image quality caused by stray light is suppressed, while both a sensitive level and a non-sensitive level are properly set in accordance with a type of photosensitive material. In the image exposing apparatus, a recording level setting unit calculates a recording level corresponding to a light amount level stored in a recording level light amount memory and sets the calculated recording level. A non-recording level setting unit calculates a non-recording level from an extinction ratio, which corresponds to a type of photosensitive material stored in a photosensitive material information memory, and the recording level. An output voltage setting unit sets an output voltage such that a detected voltage becomes equal to one of the recording level and the non-recording level.

Abstract: In a semiconductor laser device including an active region which is made of an aluminum-free material and a plurality of cladding layers made of at least one AlGaAs or AlGaInP material, the active region includes a quantum well layer and at least one optical waveguide layer; a portion of the at least one optical waveguide layer located on one side of the quantum well layer has a thickness of 0.25 &mgr;m or more; and the at least one optical waveguide layer, other than a portion of the at least one optical waveguide layer being located near the quantum well layer and having a thickness of at least 10 nm, is doped with impurity of 1017 cm−3 or more.

Abstract: When a ratio R between a total angle &phgr; of a widening angle in a median intensity of light of a light source (a GaN based semiconductor laser) and a total angle 2/&phgr; of a widening angle of light defining a numerical aperture NA of a collimator optical system (collimator lens) is defined as R=(sin−1NA)×2/&phgr;, the numerical aperture of the collimator optical system (collimator lens) is set so that 2.0≧R≧0.58. Thus, an image exposure device is provided that can suppress stray light of a light source that emits a large amount of stray light.

Abstract: A semiconductor light emitting apparatus includes a semiconductor light emitting element which includes a stripe structure and an active layer made of an InGaN material, and emits first light without laser oscillation; an optical resonator; and a first wavelength selection unit which allows resonance, in the optical resonator, of second light having a selected wavelength included in the first light emitted by the semiconductor light emitting element. Alternatively, instead of the first wavelength selection unit, a second wavelength selection unit which allows output of only the above second light from the semiconductor light emitting apparatus may be provided. In this case, the semiconductor light emitting apparatus may further include an optical detector which detects intensity of the second light; and an output regularizing unit which drives the semiconductor light emitting element based on the detected intensity so as to regularize the intensity of the second light.

Abstract: A light source apparatus equipped with a GaN type semiconductor laser, wherein deformation of the shape of the light spot due to fluctuations in the drive current of the light emitting element is prevented, is provided. A light source apparatus equipped with a GaN type semiconductor laser is provided with a slit panel or other spatial filter for eliminating stray light, which amounts to 20% or less of the total output occurring when the GaN type semiconductor laser is driven at maximum output, from the light emitted from the GaN type semiconductor laser.

Abstract: A laser apparatus includes a semiconductor laser element, a surface-emitting semiconductor element including a first mirror, and a second mirror. The semiconductor laser element emits first laser light having a first wavelength. The surface-emitting semiconductor element is excited with the first laser light, and emits second laser light having a second wavelength which is longer than the first wavelength. The first mirror in the surface-emitting semiconductor element is arranged on one side of the first active layer. The second mirror is arranged outside the surface-emitting semiconductor element so that the first and second mirrors form a resonator in which the second laser light resonates. The surface-emitting semiconductor element includes a structure for controlling a spatial mode of the second laser light.

Abstract: In order to obtain a visually high quality image with excellent sharpness using a silver halide photosensitive material, it is necessary to reduce the ratio of EL light in the light output from a GaN based laser diode to 20% or less. For example, when the light intensity measured on a sheet of photosensitive paper is 0.05 mW, the thickness of a waveguide is 3 nm and the width of the waveguide is 3 &mgr;m, this condition is satisfied with a length of a resonator being 1 mm or less. In other words, a waveguide width W1 and a resonator length L are set such that the product of the waveguide width W1 and the resonator length L (W1·L) becomes 0.003 mm2 or less. This reduces the output ratio of the EL light, and a high quality image with excellent sharpness can be obtained when a silver halide photosensitive material is exposed.

Abstract: In a semiconductor laser device, an active region, including a quantum well layer sandwiched between upper and lower optical waveguide layers, is formed on a substrate. A near-edge portion of the active region is etched down to a mid-thickness of the lower optical waveguide layer. A non-absorbing layer, made of a semiconductor material having a bandgap greater than photon energy of laser light generated in the active region, is formed over the active region. An etching stop layer is formed at the mid-thickness location in the lower optical waveguide layer so as to selectively stop the etching of the near-edge portion of the active region. An electron barrier layer, made of a semiconductor material having a bandgap greater than the bandgap of the upper optical waveguide layer, is formed at a mid-thickness location in the upper optical waveguide layer.

Abstract: A semiconductor light emitting apparatus includes a semiconductor light emitting element which includes a stripe structure and an active layer made of an InGaN material, and emits first light without laser oscillation; an optical resonator; and a first wavelength selection unit which allows resonance, in the optical resonator, of second light having a selected wavelength included in the first light emitted by the semiconductor light emitting element. Alternatively, instead of the first wavelength selection unit, a second wavelength selection unit which allows output of only the above second light from the semiconductor light emitting apparatus may be provided. In this case, the semiconductor light emitting apparatus may further include an optical detector which detects intensity of the second light; and an output regularizing unit which drives the semiconductor light emitting element based on the detected intensity so as to regularize the intensity of the second light.

Abstract: An optical recording method in which an effective recording sensitivity in the recording of image information on a photosensitive material is raised, whereby a productivity is enhanced owing to lowered energy (laser power) required for the recording or a heightened recording speed. An image is recorded by projecting a light beam onto the photosensitive material formed on a base material backing. The optical recording method includes the steps of: (a) successively outputting pulse light whose duty factor is at most 50%, from a light source; (b) modulating the pulse light output from the light source, in accordance with an image signal, and then projecting the modulated pulse light onto the photosensitive material; and (c) recording the image by causing the pulse light to scan the photosensitive material.

Abstract: A fluorescence observing apparatus including a light source for emitting excitation light, an excitation light irradiation section for irradiating the excitation light to a sample, and a fluorescence measurement section for measuring fluorescence emitted from the sample by the irradiation of the excitation light. The temperature of the light source is always sensed by a thermistor, and a Peltier element disposed in direct contact with the light source is cooled by a control section so that the temperature of the light source is maintained at 20° C. or less.