Abstract: A fluid analyzer includes a substrate, a quantum cascade laser formed on a surface of the substrate and including a first light-emitting surface and a second light-emitting surface facing each other in a predetermined direction parallel to the surface, a quantum cascade detector formed on the surface and including the same layer structure as the quantum cascade laser and a light incident surface facing the second light-emitting surface in the predetermined direction, and an optical element disposed on an optical path of light emitted from the first light-emitting surface across an inspection region in which a fluid to be analyzed is to be disposed and reflecting the light to feed the light back to the first light-emitting surface.

Abstract: An optical semiconductor element includes: an optical waveguide body; a first electrode that is disposed on a second clad layer; a second electrode that is disposed on the second clad layer on one side of the first electrode in a light guiding direction of the optical waveguide body; a third electrode that is disposed on the second clad layer on the other side of the first electrode in the light guiding direction; and at least one fourth electrode that faces the first electrode, the second electrode, and the third electrode with the optical waveguide body interposed therebetween. The optical waveguide body includes a first separation region that electrically separates a first region under the first electrode from a second region under the second electrode and a second separation region that electrically separates the first region under the first electrode and a third region under the third electrode.

Abstract: A quantum cascade laser is configured with a semiconductor substrate, and an active layer provided on a first surface of the substrate and having a cascade structure in the form of a multistage lamination of unit laminate structures each of which includes an emission layer and an injection layer. The active layer is configured to be capable of generating first pump light of a frequency ?1 and second pump light of a frequency ?2 by intersubband emission transitions of electrons, and to generate output light of a difference frequency ? by difference frequency generation from the first pump light and the second pump light. Grooves respectively formed in a direction intersecting with a resonating direction in a laser cavity structure are provided on a second surface opposite to the first surface of the substrate.

Abstract: A quantum cascade laser is configured with a semiconductor substrate, and an active layer provided on a first surface of the substrate and having a multistage lamination of unit laminate structures each of which includes an emission layer and an injection layer. The active layer is configured to be capable of generating first pump light of a frequency ?1 and second pump light of a frequency ?2, and to generate output light of a difference frequency ? by difference frequency generation. An external diffraction grating is provided constituting an external cavity for generating the first pump light and configured to be capable of changing the frequency ?1, outside an element structure portion including the active layer. Grooves respectively formed in a direction intersecting with a resonating direction are provided on a second surface of the substrate.

Abstract: A quantum cascade detector includes a semiconductor substrate; an active layer having a cascade structure; a lower cladding layer provided between the active layer and the substrate and having a lower refractive index than the active layer; a lower metal layer provided between the lower cladding layer and the substrate; an upper cladding layer provided on an opposite side to the substrate with respect to the active layer and having a lower refractive index than the active layer; and an upper metal layer provided on an opposite side to the active layer with respect to the upper cladding layer. A first end face being in a waveguide direction in a waveguide structure with the active layer, lower cladding layer, and upper cladding layer is an entrance surface for light to be detected.

Abstract: A quantum cascade laser is configured with a semiconductor substrate, and an active layer having a multistage lamination of emission layers and injection layers. The active layer is configured to be capable of generating first pump light of a frequency ?1 and second pump light of a frequency ?2, and to generate output light of a difference frequency ? by difference frequency generation. An external diffraction grating is provided for generating the first pump light, outside an element structure portion including the active layer, and an internal diffraction grating is provided for generating the second pump light, inside the element structure portion. The frequency ?2 is set to be fixed to a frequency not coincident with a gain peak, and the frequency ?1 is set to be variable to a frequency different from the frequency ?2.

Abstract: A quantum cascade detector includes a semiconductor substrate; an active layer having a cascade structure; a lower cladding layer provided between the active layer and the substrate and having a lower refractive index than the active layer; a lower metal layer provided between the lower cladding layer and the substrate; an upper cladding layer provided on an opposite side to the substrate with respect to the active layer and having a lower refractive index than the active layer; and an upper metal layer provided on an opposite side to the active layer with respect to the upper cladding layer. A first end face being in a waveguide direction in a waveguide structure with the active layer, lower cladding layer, and upper cladding layer is an entrance surface for light to be detected.

Abstract: A quantum cascade laser is configured with a semiconductor substrate, and an active layer having a multistage lamination of emission layers and injection layers. The active layer is configured to be capable of generating first pump light of a frequency ?1 and second pump light of a frequency ?2, and to generate output light of a difference frequency ? by difference frequency generation. An external diffraction grating is provided for generating the first pump light, outside an element structure portion including the active layer, and an internal diffraction grating is provided for generating the second pump light, inside the element structure portion. The frequency ?2 is set to be fixed to a frequency not coincident with a gain peak, and the frequency ?1 is set to be variable to a frequency different from the frequency ?2.

Abstract: A quantum cascade laser is configured with a semiconductor substrate, and an active layer provided on a first surface of the substrate and having a multistage lamination of unit laminate structures each of which includes an emission layer and an injection layer. The active layer is configured to be capable of generating first pump light of a frequency ?1 and second pump light of a frequency ?2, and to generate output light of a difference frequency ? by difference frequency generation. An external diffraction grating is provided constituting an external cavity for generating the first pump light and configured to be capable of changing the frequency ?1, outside an element structure portion including the active layer. Grooves respectively formed in a direction intersecting with a resonating direction are provided on a second surface of the substrate.

Abstract: A quantum cascade laser is configured with a semiconductor substrate, and an active layer provided on a first surface of the substrate and having a cascade structure in the form of a multistage lamination of unit laminate structures each of which includes an emission layer and an injection layer. The active layer is configured to be capable of generating first pump light of a frequency ?1 and second pump light of a frequency ?2 by intersubband emission transitions of electrons, and to generate output light of a difference frequency ? by difference frequency generation from the first pump light and the second pump light. Grooves respectively formed in a direction intersecting with a resonating direction in a laser cavity structure are provided on a second surface opposite to the first surface of the substrate.

Abstract: A quantum cascade laser is configured with a semiconductor substrate and first and second active layers provided in series on the substrate. A unit laminate structure of the first active layer has a subband level structure having an emission upper level and an emission lower level, and is configured so as to be able to generate light of a first frequency ?1, a unit laminate structure of the second active layer has a subband level structure having a first emission upper level, a second emission upper level, and a plurality of emission lower levels, and is configured so as to be able to generate light of a second frequency ?2, and light of a difference frequency ? is generated by difference frequency generation from the light of the first frequency ?1 and the light of the second frequency ?2.

Abstract: A photodetector 1A comprises a multilayer structure 3 having a first layer 4 constituted by first metal or first semiconductor, a semiconductor structure layer 5 mounted on the first layer 4 and adapted to excite an electron by plasmon resonance, and a second layer 6 mounted on the semiconductor structure layer 5 and constituted by second metal or second semiconductor.

Abstract: A quantum cascade laser is configured with a semiconductor substrate and first and second active layers provided in series on the substrate. A unit laminate structure of the first active layer has a subband level structure having an emission upper level and an emission lower level, and is configured so as to be able to generate light of a first frequency ?1, a unit laminate structure of the second active layer has a subband level structure having a first emission upper level, a second emission upper level, and a plurality of emission lower levels, and is configured so as to be able to generate light of a second frequency ?2, and light of a difference frequency ? is generated by difference frequency generation from the light of the first frequency ?1 and the light of the second frequency ?2.

Abstract: A quantum cascade detector includes a semiconductor substrate, and an active layer formed by laminating unit laminate structures each having an absorption region with a first barrier layer to a second well layer and a transport region with a third barrier layer to an n-th well layer. A second absorption well layer has a layer thickness ½ or less of that of a first absorption well layer thickest in one period, and a coupling barrier layer has a layer thickness smaller than that of an exit barrier layer thickest in one period. The unit laminate structure has a detection lower level arising from a ground level in the first well layer, a detection upper level generated by coupling an excitation level in the first well layer and a ground level in the second well layer, and a transport level structure for electrons.

Abstract: A microparticle dispersion liquid manufacturing apparatus 10 includes a controller 11, a light source 12, an irradiation optical system 13, and a container 14. A solid object 1 is contained in and a solvent 2 is injected into an interior of the container 14 to enable attainment of a state where the solid object 1 is in contact with the solvent 2. The light source 12 repeatedly outputs pulsed light. By repeatedly irradiating the solvent 2 with the pulsed light from the light source 12, expansion and contraction of the solvent 2 is made to occur repeatedly at the irradiated portion, thereby generating a pressure wave in the solvent 2, and the pressure wave is made to act on the solid object 1 to finely pulverize the solid object 1 and thereby manufacture a microparticle dispersion liquid in which microparticles are dispersed in the solvent.

Abstract: A quantum cascade detector includes a semiconductor substrate, and an active layer formed by laminating unit laminate structures each having an absorption region with a first barrier layer to a second well layer and a transport region with a third barrier layer to an n-th well layer. A second absorption well layer has a layer thickness ½ or less of that of a first absorption well layer thickest in one period, and a coupling barrier layer has a layer thickness smaller than that of an exit barrier layer thickest in one period. The unit laminate structure has a detection lower level arising from a ground level in the first well layer, a detection upper level generated by coupling an excitation level in the first well layer and a ground level in the second well layer, and a transport level structure for electrons.

Abstract: A photodetector 1A comprises an optical element 10, having a structure including first regions and second regions periodically arranged with respect to the first regions along a plane perpendicular to a predetermined direction, for generating an electric field component in the predetermined direction when light is incident thereon along the predetermined direction; and a semiconductor multilayer body 4 having a quantum cascade structure, arranged on the other side opposite from one side in the predetermined direction with respect to the optical element, for producing a current according to the electric field component in the predetermined direction generated by the optical element 10; while the quantum cascade structure includes an active region 4b for exciting an electron and an injector region 4c for transporting the electron, the active region 4b being formed on the outermost surface on the one side of the injector region 4c in the quantum cascade structure.

Abstract: A photodetector 1A comprises an optical element 10, having a structure including first regions and second regions periodically arranged with respect to the first regions along a plane perpendicular to a predetermined direction, for generating an electric field component in the predetermined direction when light is incident thereon along the predetermined direction; arid a semiconductor multilayer body 4 having a quantum cascade structure, arranged on the other side opposite from one side in the predetermined direction with respect to the optical element, for producing a current according to the electric field component in the predetermined direction generated by the optical element 10; while the quantum cascade structure includes an active region 4b having a first upper quantum level and a second upper quantum level lower than the first upper quantum level, and an injector region 4c for transporting an electron excited by the active region 4b.

Abstract: An optical element 10 for transmitting light therethrough along a predetermined direction and modulating the light comprises a structure 11 having a first region R1 and a second region R2 periodically arranged with respect to the first region R1 along a plane perpendicular to the predetermined direction, the first and second regions R1, R2 having respective refractive indexes different from each other, and properties of transmitting the light therethrough.

Abstract: A quantum cascade laser is configured to include a semiconductor substrate, and an active layer that is provided on the substrate and has a cascade structure formed by alternately laminating emission layers and injection layers by multistage-laminating unit laminate structures each consisting of the quantum well emission layer and the injection layer, and generates light by intersubband transition in a quantum well structure. In a laser cavity structure for light with a predetermined wavelength generated in the active layer, a front reflection film with a reflectance of not less than 40% and not more than 99% for laser oscillation light is formed on the front end face that becomes a laser beam output surface, and a back reflection film with a reflectance higher than that of the front reflection film for the laser oscillation light is formed on the back end face.