Abstract: A detector includes an active layer containing a quantum well or quantum dots and the detector can shift a detection wavelength by applying a voltage to the active layer. The detector has a reference wavelength to be referred to as a criterion for calibration or correction of the detection wavelength within a range in which the detection wavelength is shifted. A method of calibrating or correcting with the detector, a detection wavelength with the reference wavelength being defined as the criterion is provided.

Abstract: An image projection device includes: one light source unit emitting an image light beam, which forms an image, of visible light and a checking light beam of visible light; an optical system projecting the image light beam emitted from the one light source unit onto a first surface region of an eye of a user to project the image light beam onto a retina of the user, and projecting the checking light beam emitted from the one light source unit onto a second surface region, which is distant from the first surface region, of the eye of the user; a light detector detecting a reflected light that is the checking light beam reflected by the eye of the user; and a controller controlling at least one of the one light source unit and the optical system based on a detection result of the reflected light by the light detector.

Abstract: A photodetector including a substrate, a light absorption layer arranged over the substrate, the light absorption layer including a stack including a semiconductor layer that absorbs light of a wavelength having an electric field vector parallel to a normal direction of a substrate surface, a lower contact layer arranged on a first side of the light absorption layer, a lower electrode contacting with the lower contact layer, an upper contact layer arranged on a second side of the light absorption layer, and an upper electrode contacting with the upper contact layer. An uneven structure including polarization-selective shapes of projections or depressions on the second side of the upper contact layer is provided, the shapes of projections or depressions each having a size of a wavelength or less of incident light in the semiconductor layer and half the wavelength or greater and being periodically arranged in at least one direction.

Abstract: A semiconductor light source includes a substrate, an optical waveguide having a reflection structure provided on the substrate with an oxide film in between and a semiconductor light emitting element provided on the optical waveguide. The optical waveguide includes a constant width core layer portion located in a center portion, tapered core layer portions that are provided on either side of the constant width core layer and of which the core width gradually increases and a constant width core layer portion for an optical wire waveguide. The semiconductor light emitting element is placed so as to cover at least a portion of the tapered core layer portions on both sides.

Abstract: A photoelectric conversion element includes a buffer layer, a BSF layer, a base layer, a photoelectric conversion layer, an emitter layer, a window layer, a contact layer, and a p-type electrode sequentially on one surface of a substrate, and includes an n-type electrode on the other surface of the substrate. The photoelectric conversion layer has at least one quantum dot layer. The at least one quantum dot layer includes a quantum dot and a barrier layer. A photoelectric conversion member including the buffer layer, the BSF layer, the base layer, the photoelectric conversion layer, the emitter layer, the window layer, and the contact layer has an edge of incidence that receives light in an oblique direction relative to the growth direction of the quantum dot. A concentrator concentrates sunlight and causes the concentrated sunlight to enter the photoelectric conversion member from the edge of incidence.

Abstract: A quantum cascade laser includes a semiconductor substrate and an active layer having a cascade structure, in which unit layered bodies, each composed of a quantum well light emitting layer and an injection layer, are stacked, wherein the unit layered body has a subband level structure having an upper laser level, a lower laser level, and a relaxation miniband composed of at least two energy levels with an energy spacing smaller than the energy difference (EUL) between the upper laser level and the lower laser level, the energy width of the relaxation miniband is smaller than the energy (ELO?EUL) obtained by subtracting the energy difference (EUL) from the energy (ELO) of longitudinal optical phonons, and electrons subjected to the intersubband transition are relaxed in the relaxation miniband and are injected into a quantum well light emitting layer in a subsequent unit layered body.

Abstract: A nitride semiconductor device includes a GaN substrate in which an angle between a principal surface and an m-plane of GaN is ?5° or more and +5° or less, a first intermediate layer disposed on the principal surface of the substrate and made of AlzGa(1-z)N (0?z?1), and a second intermediate layer disposed on a principal surface of the first intermediate layer, having an Al content different from that of the first intermediate layer, and made of Alx1Iny1Ga(1-x1-y1) (0?x1?1, 0?y1?1). A quantum cascade laser includes the nitride semiconductor device.

Abstract: A photoelectric conversion element includes a photoelectric conversion layer having the quantum structure and utilizes intersubband transition in a conduction band. The photoelectric conversion element includes a superlattice semiconductor layer in which a barrier layer and a quantum dot layer as a quantum layer are alternately and repeatedly stacked. The barrier layer includes an indirect transition semiconductor material, and the quantum dot layer has a nano-structure including a direct transition semiconductor material. The indirect transition semiconductor material constituting the barrier layer has a bandgap of more than 1.42 eV at room temperature.

Abstract: A QCL (10) includes a first electrode (15), a first contact layer (11) that is in contact with the first electrode (15) and is made of a first compound semiconductor, a second electrode (14) having a polarity opposite to that of the first electrode (15), a second contact layer (13) that is in contact with the second electrode (14) and is made of a second compound semiconductor, and an active layer (12) disposed between the first contact layer (11) and the second contact layer (13) and including two or more active layer units. Each of the active layer units includes one or more quantum well layers made of a third compound semiconductor and one or more barrier layers made of a fourth compound semiconductor, and each of the quantum well layers and each of the barrier layers are alternately stacked.

Abstract: A photodetector including a substrate, a light absorption layer arranged over the substrate, the light absorption layer including a stack including a semiconductor layer that absorbs light of a wavelength having an electric field vector parallel to a normal direction of a substrate surface, a lower contact layer arranged on a first side of the light absorption layer, a lower electrode contacting with the lower contact layer, an upper contact layer arranged on a second side of the light absorption layer, and an upper electrode contacting with the upper contact layer. An uneven structure including polarization-selective shapes of projections or depressions on the second side of the upper contact layer is provided, the shapes of projections or depressions each having a size of a wavelength or less of incident light in the semiconductor layer and half the wavelength or greater and being periodically arranged in at least one direction.

Abstract: A semiconductor light source includes a substrate, an optical waveguide having a reflection structure provided on the substrate with an oxide film in between and a semiconductor light emitting element provided on the optical waveguide. The optical waveguide includes a constant width core layer portion located in a center portion, tapered core layer portions that are provided on either side of the constant width core layer and of which the core width gradually increases and a constant width core layer portion for an optical wire waveguide. The semiconductor light emitting element is placed so as to cover at least a portion of the tapered core layer portions on both sides.

Abstract: A photoelectric conversion element includes a superlattice semiconductor layer including barrier sub-layers and quantum sub-layers (quantum dot sub-layers) alternately stacked and also includes a wavelength conversion layer containing a wavelength conversion material converting the wavelength of incident light. The wavelength conversion layer converts incident light into light with a wavelength corresponding to an optical transition from a quantum level of the conduction band of the superlattice semiconductor layer to a continuum level of the conduction band.

Abstract: A photoelectric conversion element according to the present invention includes a photoelectric conversion layer. The photoelectric conversion layer includes a p-type semiconductor layer, an n-type semiconductor layer, and a superlattice semiconductor layer which is interposed between the p-type semiconductor layer and the n-type semiconductor layer. The superlattice semiconductor layer has a superlattice structure in which barrier layers and quantum layers are stacked alternately and repeatedly, and is provided so as to form an intermediate energy band between an upper end of a valence band of the barrier layer and a lower end of a conduction band of the barrier layer.

Abstract: A photoelectric conversion element includes a superlattice semiconductor layer including barrier sub-layers and quantum sub-layers (quantum dot sub-layers) alternately stacked and also includes a wavelength conversion layer containing a wavelength conversion material converting the wavelength of incident light. The wavelength conversion layer converts incident light into light with a wavelength corresponding to an optical transition from a quantum level of the conduction band of the superlattice semiconductor layer to a continuum level of the conduction band.

Abstract: The present invention is an image projection device that includes: a light source 12 that emits a laser beam 34; a scanning mirror 14 that two-dimensionally scans the laser beam 34 emitted from the light source 12; and a projection mirror 24 that projects scanned light onto a retina 26 of an eyeball 22 of a user to project an image onto the retina 26, the scanned light being composed of the laser beam 34 that has been scanned by the scanning mirror 14, wherein the laser beam 34 emitted from the light source 12 is scanned by using a part of an operating range of the scanning mirror 14.

Abstract: A photoelectric conversion element according to the present invention includes a photoelectric conversion layer. The photoelectric conversion layer includes a p-type semiconductor layer, an n-type semiconductor layer, and a superlattice semiconductor layer which is interposed between the p-type semiconductor layer and the n-type semiconductor layer. The superlattice semiconductor layer has a superlattice structure in which barrier layers and quantum layers are stacked alternately and repeatedly, and is provided so as to form an intermediate energy band between an upper end of a valence band of the barrier layer and a lower end of a conduction band of the barrier layer.

Abstract: A method for manufacturing a semiconductor light emitting device includes forming a lower cladding layer over a GaAs substrate; forming a quantum dot active layer over the lower cladding layer; forming a first semiconductor layer over the quantum dot active layer; forming a diffraction grating by etching the first semiconductor layer; forming a second semiconductor layer burying the diffraction grating; and forming an upper cladding layer having a conductive type different from that of the lower cladding layer over the second semiconductor layer, wherein the processes after forming the quantum dot active layer are performed at a temperature not thermally deteriorating or degrading quantum dots included in the quantum dot active layer.

Abstract: An active layer (18) is formed over a semiconductor substrate having a pair of facets (15A, 15B) mutually facing opposite directions. An upper cladding layer (19) is formed on the active layer, having a refractive index lower than that of the active layer. A diffraction grating (25) is disposed in the upper cladding layer on both sides of a distributed feedback region in a waveguide region (22), the waveguide region extending from one facet to the other of the semiconductor substrate. End regions (22B) are defined at both ends of the waveguide region and the distributed feedback region (22A) is disposed between the end regions. Low refractive index regions (26) are disposed in the upper cladding layer on both sides of each of the end regions of the waveguide region, the low refractive index regions having a refractive index lower than that of the upper cladding layer.

Abstract: An solar cell of the present invention includes a p-type semiconductor layer, an n-type semiconductor layer, and a superlattice semiconductor layer interposed between the p-type semiconductor layer and the n-type semiconductor layer, in which the superlattice semiconductor layer has a superlattice structure in which barrier layers and quantum dot layers each including a plurality of quantum dots are stacked alternately and repeatedly, the superlattice semiconductor layer contains an n-type dopant and has at least two intermediate energy levels at which electrons photoexcited from the valence band of the quantum dots or the barrier layers can be present for a certain period of time, each of the intermediate energy levels is located between the top of the valence band of the barrier layers and the bottom of the conduction band of the barrier layers, each of the intermediate energy levels is formed from one or a plurality of quantum levels of the quantum dots, and the superlattice semiconductor layer contains an

Abstract: A semiconductor light emitting device includes a lower cladding layer, an active layer, and an AlGaAs upper cladding layer mounted on a GaAs substrate. The semiconductor light emitting device has a ridge structure including the AlGaAs upper cladding layer. The semiconductor light emitting device further includes an InGaAs etching stop layer provided in contact with the lower side of the AlGaAs upper cladding layer. The InGaAs etching stop layer has a band gap greater than that of the active layer.