Abstract: A two-dimensional photonic-crystal laser includes: a substrate made of an n-type semiconductor; a p-type cladding layer on an upper side of the substrate made of a p-type semiconductor; an active layer on an upper side of the cladding layer; a two-dimensional photonic-crystal layer on an upper side of the active layer including a plate-shaped base body made of an n-type semiconductor wherein modified refractive index areas whose refractive index differs from the base body are arranged; a first tunnel layer between the substrate and cladding layer made of an n-type semiconductor having a carrier density higher than the substrate's; a second tunnel layer between the first tunnel and cladding layers, made of a p-type semiconductor having a carrier density higher than the p-type semiconductor layer's; a first electrode on a lower side of or in the substrate; and a second electrode on an upper side of the two-dimensional photonic-crystal layer.

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 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: 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: 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: 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 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.

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: 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: An objective of the present invention is to provide a surface emitting laser capable of selectively generating a laser oscillation in the fundamental mode and thereby emitting a single-wavelength laser light. In a surface emitting laser including an active layer and a two-dimensional photonic crystal provided on one side of the active layer, a reflector 45 or 46 is provided at least at a portion of the circumference of the two-dimensional photonic crystal. The reflector has a reflectance distribution in which the reflectance has a maximum value at a position where the amplitude envelope of the fundamental mode of an internal resonance light created within the two-dimensional photonic crystal. This design strengthens the fundamental mode while suppressing the second mode, thus enabling the laser oscillation in the fundamental mode to be selectively obtained, so that a single-wavelength laser light can be emitted.

Abstract: The two-dimensional photonic crystal surface emitting laser according to the present invention includes a number of main modified refractive index areas periodically provided in a two-dimensional photonic crystal and secondary structures each relatively located in a similar manner to each of the main modified refractive index areas. The location of the secondary structure is determined so that a main reflected light which is reflected by a main modified refractive index area and a secondary reflected light which is reflected by a secondary structure are weakened or intensified by interference.

Abstract: The two-dimensional photonic crystal surface emitting laser according to the present invention includes a semiconductor substrate, a main laser section and a reflection film. The main laser section includes a lower cladding layer, an active layer, a two-dimensional photonic crystal layer, an upper cladding layer and a contact layer, which are all deposited on the semiconductor substrate. The reflection film, which surrounds the entire side surfaces of the main laser section, is made of a thin titanium-gold film deposited by sputtering.

Abstract: An objective of the present invention is to provide a surface emitting laser capable of selectively generating a laser oscillation in the fundamental mode and thereby emitting a single-wavelength laser light. In a surface emitting laser including an active layer and a two-dimensional photonic crystal provided on one side of the active layer, a reflector 45 or 46 is provided at least at a portion of the circumference of the two-dimensional photonic crystal. The reflector has a reflectance distribution in which the reflectance has a maximum value at a position where the amplitude envelope of the fundamental mode of an internal resonance light created within the two-dimensional photonic crystal. This design strengthens the fundamental mode while suppressing the second mode, thus enabling the laser oscillation in the fundamental mode to be selectively obtained, so that a single-wavelength laser light can be emitted.