Abstract: The spectrometer includes: a light source unit emitting a laser beam; a mirror unit including a first plane mirror having a first mirror surface and a second plane mirror having a second mirror surface, wherein a measurement target is introduced between the first mirror surface and the second mirror surface; and a light detector detecting the laser beam returned by multiple reflection between the first mirror surface and the second mirror surface. The first mirror surface and the second mirror surface are arranged non-parallel to each other when viewed from the Z-axis direction so as to form an optical path of the laser beam reciprocating in the Y-axis direction while performing multiple reflection between the first mirror surface and the second mirror surface. The optical path of the laser beam between the first mirror surface and the second mirror surface is inclined with respect to the Z-axis direction.

Abstract: A QCL module according to an embodiment includes a package accommodating a QCL element and provided with a window material for extracting a laser beam emitted from the QCL element to the outside, a lens hold member for holding a lens on which the laser beam output from the window material is incident, a cooling fan for cooling the package, and a base for holding the package, the lens hold member, and the cooling fan. The package and the lens hold member are fastened together to the base by a common screw member.

Abstract: Disclosed is an optical kit for forming an optical system including an external resonator of a laser light source that outputs laser light, the optical kit including: a base including a main surface; a light source holding part provided on the main surface for holding the laser light source; and a holding part provided on the main surface for holding the optical system, wherein the holding part has a reflector holding part for holding the corner reflector, a first opening member holding part for holding the first opening member, and a second opening member holding part for holding the second opening member, and wherein the first opening member holding part is positioned closer to the reflector holding part than an emission surface of the laser light of the laser light source held by the light source holding part.

Abstract: A photodetection module includes a photodetector and a fixing member. The photodetector includes a semiconductor substrate, a mesa portion, a first contact layer, a second contact layer, and a first electrode formed in a planar shape on a major surface of the semiconductor substrate, and electrically connected to one of the first contact layer and the second contact layer. The fixing member includes an insulating substrate, and a first wiring formed in a planar shape on a major surface of the insulating substrate. A recessed portion is formed in the major surface of the insulating substrate, and at least a part of the mesa portion is disposed inside the recessed portion. The first electrode is electrically connected to the first wiring in a state where the first electrode is in surface contact with the first wiring.

Abstract: A photodetector includes: a semiconductor substrate; a mesa portion formed on a major surface of the semiconductor substrate to extend along an optical waveguide direction; a first contact layer; a second contact layer; a first electrode; and an air bridge wiring electrically connected to the first contact layer and the first electrode. When viewed in a direction perpendicular to the major surface of the semiconductor substrate, a length of the mesa portion in the optical waveguide direction is longer than a length of the mesa portion in a direction perpendicular to the optical waveguide direction. The air bridge wiring is led out from the first contact layer to one side in the direction perpendicular to the optical waveguide direction, and is bridged between the first contact layer and the first electrode.

Abstract: The laser module includes a QCL element, a diffraction grating unit including a movable diffraction grating, a first lens that transmits light emitted from an end surface of the QCL element and light returning from the movable diffraction grating to the QCL element, a second lens that transmits terahertz waves emitted from the QCL element, a first holder, and a package. The first holder has a support surface on which the QCL element is mounted and a side surface connected to the support surface and facing the first lens in a resonance direction. A distance from an intersection point between the side surface and the support surface to the end surface along the resonance direction is smaller than a distance between the intersection point and the first lens along the resonance direction.

Abstract: The external cavity laser module includes a quantum cascade laser element, a MEMS diffraction grating, a support plate having a first surface on which the quantum cascade laser element and the MEMS diffraction grating are disposed and a second surface opposite to the first surface, and a cooling element disposed on a side facing the second surface of the support plate to overlap with the quantum cascade laser element and the MEMS diffraction grating. In the second surface of the support plate, a concave portion recessed in a direction from the second surface toward the first surface is provided in at least a region overlapping with the quantum cascade laser element and the MEMS diffraction grating when viewed from the thickness direction. At least a portion of the cooling element facing the support plate is inserted into the concave portion.

Abstract: A beating spectroscopy device includes: first and second quantum cascade lasers; a quantum cascade detector; and a sample holder configured to hold a sample on an optical path between the second quantum cascade laser and the quantum cascade detector. Lights from the first and second quantum cascade lasers are detected by the quantum cascade detector while a wavelength of the light from the second quantum cascade laser is changed to scan a frequency of a beating signal having a frequency in accordance with a wavelength difference between the lights from the first and second quantum cascade lasers.

Abstract: A quantum cascade laser includes a semiconductor substrate, an optical waveguide formed on a first surface of the semiconductor substrate, and a temperature adjusting member. The optical waveguide includes a first region and a second region located on one side with respect to the first region in the optical waveguide direction of the optical waveguide. The first region generates a first light having a first wavelength, and the second region generates a second light having a second wavelength. The optical waveguide generates an output light having a frequency corresponding to a difference between the first wavelength and the second wavelength by difference-frequency generation. A recess for suppressing heat transfer between the first region and the second region is formed at a second surface of the semiconductor substrate. The temperature adjusting member includes a first temperature adjusting member for adjusting the temperature of the second region.

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: An optical kit includes a base including a main surface; and a holding unit provided on the main surface to hold an optical system. The holding unit includes a lens holding unit that holds a lens, a reflector holding unit that holds a corner reflector, a first aperture member holding unit that holds a first aperture member, a second aperture member holding unit that holds a second aperture member, and a third aperture member holding unit that holds a third aperture member. The reflector holding unit includes a first mechanism that holds an entirety of the corner reflector so as to be rotatable along the main surface, and a second mechanism configured to adjust an optical axis of a diffracted light in each of a reflective diffraction grating and a mirror.

Abstract: An optical semiconductor element includes a semiconductor substrate, a first laminated structure provided on a front surface of the semiconductor substrate, and a second laminated structure provided on the front surface of the semiconductor substrate, the first laminated structure includes a first quantum cascade region, the second laminated structure includes a dummy region having the same layer structure as the first quantum cascade region, a second quantum cascade region provided on the front surface of the semiconductor substrate via the dummy region, and one of the first quantum cascade region and the second quantum cascade region is a quantum cascade laser, and the other of the first quantum cascade region and the second quantum cascade region is a quantum cascade detector.

Abstract: A movable diffraction grating includes; a supporting portion; a movable portion which includes a first surface and is swingably connected with the supporting portion; a resin layer which is provided on the first surface and includes a diffraction grating pattern formed therein; a reflection layer which is provided on the resin layer an along the diffraction grating pattern and is formed of metal; and a stress regulation portion inducing stress on the movable portion, and the first surface is caused to bend concavely by stress.

Abstract: A light source module includes a light source; an optical fiber configured to guide light output from the light source; a pair of holding members configured to hold both ends of a first portion of the optical fiber such that the first portion extends linearly; a first vibrator configured to vibrate the first portion along a first direction intersecting an extending direction of the first portion; and a second vibrator configured to vibrate the first portion along a second direction intersecting the extending direction and differing from the first direction.