Abstract: Provided is a photosensor that measures a state of a detection subject, the photosensor including a light source that emits irradiation light in a wavelength band including a specific peak wavelength to the detection subject, a band-pass filter that allows the irradiation light reflected by the detection subject to be selectively transmitted through the band-pass filter, a light receiver that receives the irradiation light transmitted through the band-pass filter, and a measuring device that measures the state of the detection subject by using the light received by the light receiver. The light source has a temperature characteristic in which the specific wavelength peak of the emitted irradiation light shifts by a first wavelength shift amount depending on an environmental temperature. The band-pass filter has a temperature characteristic in which the specific wavelength peak of the emitted irradiation light shifts by a second wavelength shift amount depending on the environmental temperature.

Abstract: The 3D sensing system includes: a PC laser array in which PC laser elements are arranged on a plane; a control unit configured to control an operation mode of a laser light source; a driving unit configured to execute a drive control of the PC laser array in accordance with an operation mode controlled by the control unit; a light receiving unit configured to receive reflected light that is laser light emitted from the PC laser array and reflected from a measuring object; a signal processing unit configured to execute signal processing of the reflected light received by the light receiving unit in accordance with the operation mode; and a distance calculation unit configure to execute calculation processing of a distance to the measuring object with respect to a signal processed by the signal processing unit, in accordance with the operation mode, and to output distance data.

Abstract: The photonic-crystal (PC) slab absorber includes: a two-dimensional (2D)-PC slab composed of semiconducting materials; and a lattice point periodically arranged in the 2D-PC slab, the lattice point for forming resonant-state which can capture an electromagnetic waves incident from an outside by resonating an electromagnetic wave in a band edge of a photonic band structure of the 2D-PC slab in the plane of the 2D-PC slab. The 2D-PC slab is doped with impurities and can absorb the captured electromagnetic wave in the band edge resonant frequency of the 2D-PC slab.

Abstract: The 2D-PC surface emitting laser includes: a PC layer; and a lattice point for forming resonant-state arranged in the photonic crystal layer, and configured so that a light wave in a band edge in photonic band structure in the PC layer is diffracted in a plane of the PC layer, and is diffracted in a surface vertical direction of the PC layer. The perturbation for diffracting the light wave in the surface vertical direction of the PC layer is applied to the lattice point for forming resonant-state. The term “perturbation” means that modulation is periodically applied to the lattice point for forming resonant-state. For example, the periodic modulation may be refractive index modulation, hole-diameter modulation, or hole-depth modulation.

Abstract: A two-dimensional photonic crystal laser according to the present invention includes a two-dimensional photonic crystal layer 15 having a base body made of Al?Ga1-?As (0<?<1) or (Al?Ga1-?)?In1-?P (0<=?<1, 0<?<1) with modified refractive index areas (air holes) 151 periodically arranged therein and an epitaxial growth layer 16 created on the two-dimensional photonic crystal layer 15 by an epitaxial method. Since Al?Ga1-?As and (Al?Ga1-?)?In1-?P are solid even at high temperatures, the air holes 151 will not be deformed in the process of creating the epitaxial growth layer 16, so that the performance of the two-dimensional photonic crystal layer 15 as a resonator can be maintained at high levels.

Abstract: The terahertz-wave connector includes: a 2D-PC slab; lattice points periodically arranged in the 2D-PC slab, the lattice points for diffracting the THz waves in PBG frequencies of photonic band structure of the 2D-PC slab in order to prohibit existence in a plane of the 2D-PC slab; a 2D-PC waveguide disposed in the 2D-PC slab and formed with a line defect of the lattice points; and an adiabatic mode converter disposed at the edge face of the 2D-PC slab to which the 2D-PC waveguide extended, the 2D-PC waveguide extended to the adiabatic mode converter. There is provided also the THz-wave IC to which such a terahertz-wave connector is applied.

Abstract: A two-dimensional photonic crystal laser according to the present invention includes a two-dimensional photonic crystal layer 15 having a base body made of Al?Ga1-?As (0<?<1) or (Al?Ga1-?)?In1-?P (0<=?<1, 0<?<1) with modified refractive index areas (air holes) 151 periodically arranged therein and an epitaxial growth layer 16 created on the two-dimensional photonic crystal layer 15 by an epitaxial method. Since Al?Ga1-?As and (Al?Ga1-?)?In1-?P are solid even at high temperatures, the air holes 151 will not be deformed in the process of creating the epitaxial growth layer 16, so that the performance of the two-dimensional photonic crystal layer 15 as a resonator can be maintained at high levels.

Abstract: The directional coupler includes: lattice points periodically arranged in the 2D-PC slab and configured to diffract optical waves, THz waves, or millimeter waves in PBG frequencies in PBG structure of the 2D-PC slab in order to prohibit existence in a plane of the 2D-PC slab; a first 2D-PC waveguide formed of a line defect; a second 2D-PC waveguide which can be mode-coupled to the first waveguide; a directional coupling unit disposed between the first waveguide and the second waveguide in two rows, and having lattice points between waveguides of which the radius is smaller than that of the lattice points, wherein in order to match the first waveguide with an operational band at a side of an input port from the directional coupling unit, the width of the second waveguide is narrowed so that the whole dispersion curve of the directional coupling unit is moved to a higher-frequency side.

Abstract: A two-dimensional photonic crystal surface emitting laser light source includes a two-dimensional photonic crystal made of a plate-shaped body material provided with a periodic arrangement of identically-shaped holes and an active layer. The hole is not located on a first half-line extending from the gravity center of the hole, while the hole is located on a second half-line extending in the direction opposite to the first half-line. Injecting electric charges into the active layer generates light, which creates an electric field encircling the gravity center. For a given point on the second half-line where the hole is located, there is no hole at a point that is symmetrical to the aforementioned point with respect to the gravity center, so that the electric field vectors at the two points do not cancel each other and the laser light is stronger than conventional examples.

Abstract: The 2D-PC SEL includes: a PC layer; and a lattice point for forming resonant-state arranged in the PC layer, and configured so that a light wave at a band edge in photonic band structure in the PC layer is diffracted in a plane of the PC layer, and is diffracted in a direction normal to the surface of the PC layer. The lattice point for forming resonant-state has two types of lattice points including a first lattice point and a second lattice point, and the shapes of the adjacent first lattice point and second lattice point are different from each other.

Abstract: The 2D-PC vertical cavity surface emitting laser includes: a PC layer; and a lattice point for forming resonant-state arranged in the photonic crystal layer, and configured so that a light wave in a band edge in photonic band structure in the PC layer is diffracted in a plane of the PC layer, and is diffracted in a surface vertical direction of the PC layer. The perturbation for diffracting the light wave in the surface vertical direction of the PC layer is applied to the lattice point for forming resonant-state. The term “perturbation” means that modulation is periodically applied to the lattice point for forming resonant-state. For example, the periodic modulation may be refractive index modulation, hole-diameter modulation, or hole-depth modulation.

Abstract: The photonic-crystal (PC) slab absorber includes: a two-dimensional (2D)-PC slab composed of semiconducting materials; and a lattice point periodically arranged in the 2D-PC slab, the lattice point for forming resonant-state which can capture an electromagnetic waves incident from an outside by resonating an electromagnetic wave in a band edge of a photonic band structure of the 2D-PC slab in the plane of the 2D-PC slab. The 2D-PC slab is doped with impurities and can absorb the captured electromagnetic wave in the band edge resonant frequency of the 2D-PC slab.

Abstract: The terahertz-wave connector includes: a 2D-PC slab; lattice points periodically arranged in the 2D-PC slab, the lattice points for diffracting the THz waves in PBG frequencies of photonic band structure of the 2D-PC slab in order to prohibit existence in a plane of the 2D-PC slab; a 2D-PC waveguide disposed in the 2D-PC slab and formed with a line defect of the lattice points; and an adiabatic mode converter disposed at the edge face of the 2D-PC slab to which the 2D-PC waveguide extended, the 2D-PC waveguide extended to the adiabatic mode converter. There is provided also the THz-wave IC to which such a terahertz-wave connector is applied.

Abstract: The present invention intends to provide a surface-emitting laser light source using a two-dimensional photonic crystal in which the efficiency of extracting light in a direction perpendicular to the surface is high. In a laser light source provided with a two-dimensional photonic crystal layer created from a plate-shaped matrix body in which a large number of holes are periodically arranged and an active layer arranged on one side of the two-dimensional photonic crystal layer, the holes are created to be columnar with a predetermined cross-sectional shape such as a circular shape, and the main axis of each of the columnar holes is tilted to a surface of the matrix body. When provided with this two-dimensional photonic crystal layer, the surface-emitting laser source using a two-dimensional photonic crystal has a Q? value (i.e.

Abstract: A photonic crystal surface emission laser includes an active layer, and a photonic crystal layer made of a plate-shaped slab provided with modified refractive index area having a refractive index different from that of the slab, the modified refractive index areas being arranged on each of the lattice points of a first rhombic-like lattice and a second rhombic-like lattice in which both diagonals are mutually parallel and only one diagonal is of a different length, wherein ax1, ax2, ay, and n satisfy the following inequality: ? 1 a x ? ? 1 - 1 a x ? ? 2 ? ( 1 a x ? ? 1 + 1 a x ? ? 2 ) 2 + ( 2 a y ) 2 ? 1 n .

Abstract: A multi-beam semiconductor laser apparatus includes three or more stripe semiconductor laser emission units which are arranged on a substrate, isolation grooves which separate the semiconductor laser emission units from each other, and pad electrodes which are disposed on outer sides of the outermost semiconductor laser emission units. The isolation grooves are formed between the pad electrodes and the semiconductor laser emission units adjacent to the pad electrodes and between adjacent semiconductor laser emission units. A distance between two isolation grooves formed on outer sides of the outermost semiconductor laser light emission units is smaller than a distance between two isolation grooves formed on both sides of inner ones of the semiconductor laser light emission units.

Abstract: A two-dimensional photonic crystal surface-emitting laser light source producing a beam without side lobes is provided. A window-shaped electrode having a central window devoid of the electrode material is provided on a device substrate. A mount surface electrode smaller than the electrode including the window is provided on a mount surface. The distance between the substrate and the active layer is larger than that between the mount surface and the active layer. When a voltage is applied, electric charges are injected into the active layer and emission is obtained. Light having a specific wavelength is amplified by a two-dimensional photonic crystal and extracted through the window without side lobes due to interference. The positioning of the active layer close to the mount surface significantly enhances the heat-radiating effect.

Abstract: A photonic crystal surface emission laser includes an active layer, and a photonic crystal layer made of a plate-shaped slab provided with modified refractive index area having a refractive index different from that of the slab, the modified refractive index areas being arranged on each of the lattice points of a first rhombic-like lattice and a second rhombic-like lattice in which both diagonals are mutually parallel and only one diagonal is of a different length, wherein ax1, ax2, ay, and n satisfy the following inequality: ? 1 a x ? ? 1 - 1 a x ? ? 2 ? ( 1 a x ? ? 1 + 1 a x ? ? 2 ) 2 + ( 2 a y ) 2 ? 1 n .

Abstract: A two-dimensional photonic crystal laser light is provided. The two-dimensional photonic crystal laser includes a two-dimensional photonic crystal made of a plate-shaped member provided with a periodic arrangement of identically-shaped modified refractive index areas having a refractive index different from that of the plate-shaped member; and an active layer provided on one side of the two-dimensional photonic crystal. The modified refractive index areas are arranged at lattice points of a lattice with a same period at least in two directions; each modified refractive index area is shaped so that a feedback strength is different with respect to directions of two primitive lattice vectors of the lattice; the two-dimensional photonic crystal has a periodic structure of a supercell, which contains a plurality of lattice points; and the sum of the feedback strengths by all modified refractive index areas in the supercell is identical in each direction of the two primitive lattice vectors.

Abstract: A laser capable of emitting multiple laser beams is provided. A two-dimensional photonic crystal laser according to the present invention has a laminated structure including an active layer, a first photonic crystal layer having a periodic distribution of refractive index with a first period, and a second photonic crystal layer having a periodic distribution of refractive index with a second period that differs from the first period. This two-dimensional photonic crystal laser can emit a main beam traveling in a direction perpendicular to the two-dimensional photonic crystals and side beams each traveling in a direction inclined with respect to the main beam. These beams can be used, for example, in a recording/reproducing device by means of an optical disk, the main beam being used for recording/reproducing information and the side beams for following up the track.