Abstract: There is provided a photodynamic diagnosis apparatus including a light source for generating a light pulse having a time width shorter than a fluorescence lifetime of a photosensitizer, and a detector for measuring a time change waveform of the fluorescence to the light pulse.

Abstract: A light-emitting element includes a mesa structure in which a first compound semiconductor layer of a first conductivity type, an active layer, and a second compound semiconductor layer of a second conductivity type are disposed in that order, wherein at least one of the first compound semiconductor layer and the second compound semiconductor layer has a current constriction region surrounded by an insulation region extending inward from a sidewall portion of the mesa structure; a wall structure disposed so as to surround the mesa structure; at least one bridge structure connecting the mesa structure and the wall structure, the wall structure and the bridge structure each having the same layer structure as the portion of the mesa structure in which the insulation region is provided; a first electrode; and a second electrode disposed on a top face of the wall structure.

Abstract: A light-emitting element includes a mesa structure in which a first compound semiconductor layer of a first conductivity type, an active layer, and a second compound semiconductor layer of a second conductivity type are disposed in that order, wherein at least one of the first compound semiconductor layer and the second compound semiconductor layer has a current constriction region surrounded by an insulation region extending inward from a sidewall portion of the mesa structure; a wall structure disposed so as to surround the mesa structure; at least one bridge structure connecting the mesa structure and the wall structure, the wall structure and the bridge structure each having the same layer structure as the portion of the mesa structure in which the insulation region is provided; a first electrode; and a second electrode disposed on a top face of the wall structure.

Abstract: A laser diode assembly includes: a mode-locked laser diode device; a diffraction grating that configures an external resonator, returns primary or more order diffracted light to the mode-locked laser diode device, and outputs 0-order diffracted light outside; and an imaging section provided between the mode-locked laser diode device and the diffraction grating and imaging an image of a light output end face of the mode-locked laser diode device on the diffraction grating.

Abstract: A light-emitting element includes a mesa structure in which a first compound semiconductor layer of a first conductivity type, an active layer, and a second compound semiconductor layer of a second conductivity type are disposed in that order, wherein at least one of the first compound semiconductor layer and the second compound semiconductor layer has a current constriction region surrounded by an insulation region extending inward from a sidewall portion of the mesa structure; a wall structure disposed so as to surround the mesa structure; at least one bridge structure connecting the mesa structure and the wall structure, the wall structure and the bridge structure each having the same layer structure as the portion of the mesa structure in which the insulation region is provided; a first electrode; and a second electrode disposed on a top face of the wall structure.

Abstract: A light-emitting element includes a mesa structure in which a first compound semiconductor layer of a first conductivity type, an active layer, and a second compound semiconductor layer of a second conductivity type are disposed in that order, wherein at least one of the first compound semiconductor layer and the second compound semiconductor layer has a current constriction region surrounded by an insulation region extending inward from a sidewall portion of the mesa structure; a wall structure disposed so as to surround the mesa structure; at least one bridge structure connecting the mesa structure and the wall structure, the wall structure and the bridge structure each having the same layer structure as the portion of the mesa structure in which the insulation region is provided; a first electrode; and a second electrode disposed on a top face of the wall structure.

Abstract: An endoscopic system according to an embodiment of the present technology includes a head-mounted display, a detector, and a controller. The head-mounted display is worn by an operator. The detector is capable of detecting a motion of the operator. The controller causes each of the plurality of head-mounted displays to individually display an image. The controller includes an endoscopic image acquisition unit capable of obtaining endoscopic image data of an affected area of a patient and an image control unit capable of controlling the endoscopic image data based on an output from each of the plurality of detectors. The controller performs control to display the image based on an output from the image control unit.

Abstract: A laser diode assembly includes: a mode-locked laser diode device; a diffraction grating that configures an external resonator, returns primary or more order diffracted light to the mode-locked laser diode device, and outputs 0-order diffracted light outside; and an imaging section provided between the mode-locked laser diode device and the diffraction grating and imaging an image of a light output end face of the mode-locked laser diode device on the diffraction grating.

Abstract: A bi-section type GaN-based semiconductor laser device that has a configuration and a structure in which damage is less likely to be caused in a region in a saturable absorption region that faces a first light emission region is provided. The semiconductor laser device includes a first light emission region, a second light emission region, a saturable absorption region sandwiched by the foregoing light emission regions, a first electrode, and a second electrode. Laser light is emitted from an end face on a second light emission region side thereof. The second electrode is configured of a first portion, a second portion, and a third portion. 1<W2-ave/W1-ave is satisfied where W1-ave is an average width of a portion having a ridge stripe structure of the first portion and W2-ave is an average width of a portion having a ridge stripe structure of the second portion.

Abstract: A laser diode device includes a laminated structure in which a first compound semiconductor layer, a third compound semiconductor layer that has a light emitting region and a saturable absorption region, and a second compound semiconductor layer are sequentially layered, a second electrode, and a first electrode. The laminated structure has ridge stripe structure. The second electrode is separated into a first section to obtain forward bias state by applying a direct current to the first electrode through the light emitting region and a second section to add electric field to the saturable absorption region by an isolation trench. When minimum width of the ridge stripe structure is WMIN, and width of the ridge stripe structure of the second section of the second electrode in an interface between the second section of the second electrode and the isolation trench is W2, 1<W2/WMIN is satisfied.

Abstract: An ultrashort pulse and ultrahigh power laser diode device capable of outputting pulse laser light having higher peak power with a simple composition and a simple structure is provided. The laser diode device includes: a laminated structure composed of a first compound semiconductor layer containing n-type impurity, an active layer having a quantum well structure, and a second compound semiconductor layer containing p-type impurity; a first electrode electrically connected to the first compound semiconductor layer; and a second electrode electrically connected to the second compound semiconductor layer, wherein the second compound semiconductor layer is provided with an electron barrier layer having a thickness of 1.5*10?8 m or more, and driving is made by a pulse current having a value 10 or more times as large as a threshold current value.

Abstract: A light-emitting element includes a mesa structure in which a first compound semiconductor layer of a first conductivity type, an active layer, and a second compound semiconductor layer of a second conductivity type are disposed in that order, wherein at least one of the first compound semiconductor layer and the second compound semiconductor layer has a current constriction region surrounded by an insulation region extending inward from a sidewall portion of the mesa structure; a wall structure disposed so as to surround the mesa structure; at least one bridge structure connecting the mesa structure and the wall structure, the wall structure and the bridge structure each having the same layer structure as the portion of the mesa structure in which the insulation region is provided; a first electrode; and a second electrode disposed on a top face of the wall structure.

Abstract: A light-emitting element includes a mesa structure in which a first compound semiconductor layer of a first conductivity type, an active layer, and a second compound semiconductor layer of a second conductivity type are disposed in that order, wherein at least one of the first compound semiconductor layer and the second compound semiconductor layer has a current constriction region surrounded by an insulation region extending inward from a sidewall portion of the mesa structure; a wall structure disposed so as to surround the mesa structure; at least one bridge structure connecting the mesa structure and the wall structure, the wall structure and the bridge structure each having the same layer structure as the portion of the mesa structure in which the insulation region is provided; a first electrode; and a second electrode disposed on a top face of the wall structure.

Abstract: Provided is an alignment method of a semiconductor optical amplifier with which optimization of coupling efficiency between incident laser light and light waveguide of the semiconductor optical amplifier is enabled without depending on an external monitoring device. The alignment method of a semiconductor optical amplifier is a method that optically amplifies laser light from a laser light source and outputs the optically amplified laser light, which adjusts relative position of the semiconductor optical amplifier with respect to the laser light entering into the semiconductor optical amplifier by flowing a given value of current to the semiconductor optical amplifier while entering the laser light from the laser light source to the semiconductor optical amplifier so that a voltage applied to the semiconductor optical amplifier becomes the maximum.

Abstract: A semiconductor optical amplifier includes: a laminated structure sequentially including a first compound semiconductor layer composed of GaN compound semiconductor and having a first conductivity type, a third compound semiconductor layer having a light amplification region composed of GaN compound semiconductor, and a second compound semiconductor layer composed of GaN compound semiconductor and having a second conductivity type; a second electrode formed on the second compound semiconductor layer; and a first electrode electrically connected to the first compound semiconductor layer. The laminated structure has a ridge stripe structure. When widths of the ridge stripe structure in a light output end face and the ridge stripe structure in a light incident end face are respectively Wout, and Win, Wout>Win is satisfied. A carrier non-injection region is provided in an internal region of the laminated structure from the light output end face along an axis line of the semiconductor optical amplifier.

Abstract: A light-emitting element includes a mesa structure in which a first compound semiconductor layer of a first conductivity type, an active layer, and a second compound semiconductor layer of a second conductivity type are disposed in that order, wherein at least one of the first compound semiconductor layer and the second compound semiconductor layer has a current constriction region surrounded by an insulation region extending inward from a sidewall portion of the mesa structure; a wall structure disposed so as to surround the mesa structure; at least one bridge structure connecting the mesa structure and the wall structure, the wall structure and the bridge structure each having the same layer structure as the portion of the mesa structure in which the insulation region is provided; a first electrode; and a second electrode disposed on a top face of the wall structure.

Abstract: A laser diode assembly includes: a mode-locked laser diode device; a diffraction grating that configures an external resonator, returns primary or more order diffracted light to the mode-locked laser diode device, and outputs 0-order diffracted light outside; and an imaging section provided between the mode-locked laser diode device and the diffraction grating and imaging an image of a light output end face of the mode-locked laser diode device on the diffraction grating.

Abstract: There is provided a photodynamic diagnosis apparatus including a light source for generating a light pulse having a time width shorter than a fluorescence lifetime of a photosensitizer, and a detector for measuring a time change waveform of the fluorescence to the light pulse.

Abstract: A bi-section type GaN-based semiconductor laser device that has a configuration and a structure in which damage is less likely to be caused in a region in a saturable absorption region that faces a first light emission region is provided. The semiconductor laser device includes a first light emission region, a second light emission region, a saturable absorption region sandwiched by the foregoing light emission regions, a first electrode, and a second electrode. Laser light is emitted from an end face on a second light emission region side thereof. The second electrode is configured of a first portion, a second portion, and a third portion. 1<W2-ave/W1-ave is satisfied where W1-ave is an average width of a portion having a ridge stripe structure of the first portion and W2-ave is an average width of a portion having a ridge stripe structure of the second portion.

Abstract: A semiconductor optical amplifier includes: a laminated structure sequentially including a first compound semiconductor layer composed of GaN compound semiconductor and having a first conductivity type, a third compound semiconductor layer having a light amplification region composed of GaN compound semiconductor, and a second compound semiconductor layer composed of GaN compound semiconductor and having a second conductivity type; a second electrode formed on the second compound semiconductor layer; and a first electrode electrically connected to the first compound semiconductor layer. The laminated structure has a ridge stripe structure. When widths of the ridge stripe structure in a light output end face and the ridge stripe structure in a light incident end face are respectively Wout, and Win, Wout>Win is satisfied. A carrier non-injection region is provided in an internal region of the laminated structure from the light output end face along an axis line of the semiconductor optical amplifier.