Abstract: A photodetection element includes an N-type silicon layer formed in a single crystal state, a P-type germanium-containing layer formed in a polycrystal state and forming a hetero PN junction between the germanium-containing layer and the silicon layer, a first electrode electrically connected to the silicon layer, and a second electrode electrically connected to the germanium-containing layer.

Abstract: A terahertz wave lens includes a substrate having a surface provided with an uneven structure that changes a phase of the terahertz wave. The uneven structure includes a plurality of holes that are periodically arranged. The uneven structure includes a plurality of regions where the plurality of holes are arranged. A height of the hole in a thickness direction of the substrate and a width of the pillar differ for each of the regions. Outer end portions of the uneven structure in the thickness direction are located on the same plane.

Abstract: A terahertz wave lens includes a substrate having a surface provided with an uneven structure that changes a phase of the terahertz wave. The uneven structure includes a plurality of holes that are periodically arranged. The uneven structure includes a plurality of regions where the plurality of holes are arranged. A height of the hole in a thickness direction of the substrate and a width of the pillar differ for each of the regions. Outer end portions of the uneven structure in the thickness direction are located on the same plane.

Abstract: A laser module including a quantum cascade laser that includes a substrate having a main surface, a first clad layer provided on the main surface, an active layer provided on the first clad layer, and a second clad layer provided on the active layer, and a lens that has a lens plane disposed at a position facing the end surface of the active layer. An end surface of the active layer constitutes a resonator that causes light of a first frequency and light of a second frequency to oscillate, and the active layer is configured to generate a terahertz wave of a differential frequency between the first frequency and the second frequency. The substrate is in direct contact or indirect contact with the lens plane, and the end surface of the active layer is inclined with respect to a portion facing the end surface in the lens plane.

Abstract: A terahertz wave lens includes a substrate having a surface provided with an uneven structure that changes a phase of the terahertz wave. The uneven structure includes a plurality of holes that are periodically arranged. The uneven structure includes a plurality of regions where the plurality of holes are arranged. A height of the hole in a thickness direction of the substrate and a width of the pillar differ for each of the regions. Outer end portions of the uneven structure in the thickness direction are located on the same plane.

Abstract: A terahertz wave lens concentrates or collimates a terahertz wave. The terahertz wave lens includes a substrate having a surface provided with an uneven structure that changes a phase of the terahertz wave. The uneven structure includes a plurality of pillars that are periodically arranged. The uneven structure includes a plurality of regions where the plurality of pillars are arranged. A height of the pillar in a thickness direction of the substrate and a width of the pillar differ for each of the regions. A distance (period) between centers of the pillars adjacent to each other is constant. Outer end portions of the uneven structure in the thickness direction are located on the same plane.

Abstract: A photodetector element according to an aspect of the present disclosure includes a semiconductor layer with an uneven structure on one surface side that is constituted of projection portions and recess portions, and converts light into surface plasmons, and a metal film that is provided on the one surface side of the semiconductor layer in a manner corresponding to the uneven structure and a Schottky junction is formed between the metal film and the semiconductor layer. The semiconductor layer is constituted of n-type conductive silicon, and the other surface side of the semiconductor layer serves as an incident surface for light. The metal film is constituted of a material including nickel which form the Schottky junction when combined with the semiconductor layer.

Abstract: A photodetection element is a photodetection element having an incidence surface for light on a back surface of a semiconductor layer, and includes a periodic nano-concave/convex structure provided on a front surface of the semiconductor layer and having convex portions and concave portions constituting a longitudinal resonator and a transverse resonator for the light incident from the incidence surface, the periodic nano-concave/convex structure converting the light into surface plasmons, and a metal film provided to cover the periodic nano-concave/convex structure, a height and an arrangement pitch of the convex portions in the periodic nano-concave/convex structure are set such that a resonance wavelength of the longitudinal resonator and a resonance wavelength of the transverse resonator match, and a thickness of the metal film is equal to or greater than 20 nm.

Abstract: A photodetection element includes a semiconductor layer having, on one surface side, a periodic concave/convex structure that includes periodic convex portions and concave portions and converts light into surface plasmon, and a metal film provided on the one surface side of the semiconductor layer in correspondence to the periodic concave/convex structure, and in the periodic concave/convex structure, a Schottky junction portion that has a Schottky junction with the metal film is provided on a base end side of the convex portion, and a non-Schottky junction portion that does not have a Schottky junction with the metal film is provided on a distal end side of the convex portion.

Abstract: A photodetector element according to an aspect of the present disclosure includes a semiconductor layer with an uneven structure on one surface side that is constituted of projection portions and recess portions, and converts light into surface plasmons, and a metal film that is provided on the one surface side of the semiconductor layer in a manner corresponding to the uneven structure and a Schottky junction is formed between the metal film and the semiconductor layer. The semiconductor layer is constituted of n-type conductive silicon, and the other surface side of the semiconductor layer serves as an incident surface for light. The metal film is constituted of a material including nickel which form the Schottky junction when combined with the semiconductor layer.

Abstract: A task circumstance processing system includes a processor that executes a process. The process includes: referencing a recognition information stored in a memory, the recognition information stores, for each of plural task processes in task definitions defining relationships between the plural task processes, recognition information for recognizing execution of each of the plural task processes, and extracting for each of the task processes a timing where the recognition information is expressed in observation data from observing circumstances of the task; and outputting a result of comparing a relationship between plural task processes that have been executed as identified by the extracted timings, against a relationship between plural task processes defined by the task definitions stored in the memory.

Abstract: A photodetection element includes a semiconductor layer having, on one surface side, a periodic concave/convex structure that includes periodic convex portions and concave portions and converts light into surface plasmon, and a metal film provided on the one surface side of the semiconductor layer in correspondence to the periodic concave/convex structure, and in the periodic concave/convex structure, a Schottky junction portion that has a Schottky junction with the metal film is provided on a base end side of the convex portion, and a non-Schottky junction portion that does not have a Schottky junction with the metal film is provided on a distal end side of the convex portion.

Abstract: A photodetection element is a photodetection element having an incidence surface for light on a back surface of a semiconductor layer, and includes a periodic nano-concave/convex structure provided on a front surface of the semiconductor layer and having convex portions and concave portions constituting a longitudinal resonator and a transverse resonator for the light incident from the incidence surface, the periodic nano-concave/convex structure converting the light into surface plasmons, and a metal film provided to cover the periodic nano-concave/convex structure, a height and an arrangement pitch of the convex portions in the periodic nano-concave/convex structure are set such that a resonance wavelength of the longitudinal resonator and a resonance wavelength of the transverse resonator match, and a thickness of the metal film is equal to or greater than 20 nm.

Abstract: A task circumstance processing system includes a processor that executes a process. The process includes: referencing a recognition information stored in a memory, the recognition information stores, for each of plural task processes in task definitions defining relationships between the plural task processes, recognition information for recognizing execution of each of the plural task processes, and extracting for each of the task processes a timing where the recognition information is expressed in observation data from observing circumstances of the task; and outputting a result of comparing a relationship between plural task processes that have been executed as identified by the extracted timings, against a relationship between plural task processes defined by the task definitions stored in the memory.

Abstract: When light is incident to an antenna layer AA6 of a photocathode AA1, light of a specific wavelength included in the incident light couples with surface plasmons in the antenna layer AA6 whereupon near-field light is outputted from a through hole AA14. The intensity of the output near-field light is proportional to and greater than the intensity of the light of the specific wavelength. The output near-field light has a wavelength that can be absorbed in a photoelectric conversion layer AA4. The photoelectric conversion layer AA4 receives the near-field light outputted from the through hole AA14. A region of the photoelectric conversion layer AA4 around the through hole AA14 absorbs the near-field light and generates photoelectrons (e?) in an amount according to the intensity of the near-field light. The photoelectrons (e?) generated in the photoelectric conversion layer AA4 are outputted to the outside.

Abstract: When light is incident to an antenna layer AA6 of a photocathode AA1, light of a specific wavelength included in the incident light couples with surface plasmons in the antenna layer AA6 whereupon near-field light is outputted from a through hole AA14. The intensity of the output near-field light is proportional to and greater than the intensity of the light of the specific wavelength. The output near-field light has a wavelength that can be absorbed in a photoelectric conversion layer AA4. The photoelectric conversion layer AA4 receives the near-field light outputted from the through hole AA14. A region of the photoelectric conversion layer AA4 around the through hole AA14 absorbs the near-field light and generates photoelectrons (e?) in an amount according to the intensity of the near-field light. The photoelectrons (e?) generated in the photoelectric conversion layer AA4 are outputted to the outside.

Abstract: A signal waveform measuring apparatus 1A is configured from: a signal optical system 11, a reference optical system 16, a time difference setting unit 12 setting a time difference between signal light L1 and reference light L2, a wavelength conversion element 20 including an aggregate of crystals of a dye molecule and generating converted light L5, which has been wavelength-converted to a shorter wavelength than incident light made incident on the crystal aggregate, at an intensity proportional to an r-th power (r>1) of the intensity of the incident light, a photodetector 30 detecting the converted light L5, generated at the element 20 at the intensity that is in accordance with the intensity of the signal light L1, the intensity of the reference light L2, and the time difference between the two, and a signal waveform analyzer 40 performing analysis of the detection result of the converted light L5 and thereby acquiring a time waveform of the signal light L1.

Abstract: A signal waveform measuring apparatus 1A is configured from: a signal optical system 11, a reference optical system 16, a time difference setting unit 12 setting a time difference between signal light L1 and reference light L2, a wavelength conversion element 20 including an aggregate of crystals of a dye molecule and generating converted light L5, which has been wavelength-converted to a shorter wavelength than incident light made incident on the crystal aggregate, at an intensity proportional to an r-th power (r>1) of the intensity of the incident light, a photodetector 30 detecting the converted light L5, generated at the element 20 at the intensity that is in accordance with the intensity of the signal light L1, the intensity of the reference light L2, and the time difference between the two, and a signal waveform analyzer 40 performing analysis of the detection result of the converted light L5 and thereby acquiring a time waveform of the signal light L1.

Abstract: There is disclosed a waveguide structure that propagates surface plasmon waves, comprising: a quantum well structure, disposed on a semiconductor substrate; wherein the quantum well structure has a quantum well layer, in turn having an intersecting region that intersects a hypothetical plane substantially orthogonal to an alignment direction of the quantum well structure with respect to the semiconductor substrate, and a real part of a dielectric constant of the quantum well structure is negative for THz waves of a predetermined wavelength.

Abstract: A wavelength-converted light generating apparatus 1A includes: an excitation light source 10 supplying excitation light L0 of a predetermined wavelength; and a wavelength conversion element 20, in which an aggregate 22 of crystals of a dye molecule is held by a holding substrate 21 and which, by incidence of the excitation light L0, generates converted light L1 that has been wavelength-converted. The excitation light source 10 supplies the excitation light L0 of a wavelength longer than an absorption edge of the dye molecule to the wavelength conversion element 20. The wavelength conversion element 20, by incidence of the excitation light L0 on the crystal aggregate 22, generates and outputs the converted light (for example, visible light) L1 that has been wavelength-converted to a shorter wavelength than the excitation light (for example, near-infrared light) L0.