US-12620774-B2 - Analysis device

US12620774B2US 12620774 B2US12620774 B2US 12620774B2US-12620774-B2

Abstract

An analysis device includes a substrate including a first surface, and a second surface positioned at a side opposite to the first surface; a light source part located at the first surface of the substrate, the light source part including a quantum cascade laser; a light detector located at the first surface of the substrate; and a wiring part located at the first surface of the substrate, the wiring part being electrically connected with the light source part and the light detector.

Inventors

Shinji Saito
Yoichiro Kurita
Rei Hashimoto
Kei Kaneko
Takayoshi Fujii

Assignees

KABUSHIKI KAISHA TOSHIBA

Dates

Publication Date: 20260505
Application Date: 20220215
Priority Date: 20210827

Claims (11)

1 . An analysis device, comprising: a substrate including a first surface, and a second surface positioned at a side opposite to the first surface; a light source part located at the first surface of the substrate, the light source part including a quantum cascade laser; a light detector located at the first surface of the substrate; and a wiring part located at the first surface of the substrate, the wiring part being electrically connected with the light source part and the light detector, wherein the substrate is transmissive to a laser light emitted by the quantum cascade laser, a laser light emitted by the quantum cascade laser travels through the substrate toward the second surface and is emitted outside the substrate from the second surface, and the light detector receives a reflected light of the laser light incident on the second surface of the substrate from the outside.
2 . The device according to claim 1 , wherein the quantum cascade laser is surface-emitting and includes a photonic crystal layer.
3 . The device according to claim 1 , wherein the light detector includes a quantum cascade detector.
4 . The device according to claim 1 , wherein the light detector includes a metal antenna.
5 . The device according to claim 1 , wherein the light source part includes a first quantum cascade laser and a second quantum cascade laser, and the first quantum cascade laser and the second quantum cascade laser have different oscillation wavelengths.
6 . The device according to claim 1 , wherein the substrate includes Si, InP, or GaAs.
7 . The device according to claim 1 , wherein the substrate includes a lens portion at the second surface.
8 . An analysis device, comprising: a substrate including a first surface, and a second surface positioned at a side opposite to the first surface; a quantum cascade element located at the first surface of the substrate, the quantum cascade element being used as a light source part and a light detector; and a wiring part located at the first surface of the substrate, the wiring part being electrically connected with the quantum cascade element, wherein the substrate is transmissive to a laser light emitted by the quantum cascade element, a laser light emitted by the quantum cascade element travels through the substrate toward the second surface and is emitted outside the substrate from the second surface, and the quantum cascade element receives a reflected light of the laser light incident on the second surface of the substrate from the outside.
9 . The device according to claim 8 , wherein the quantum cascade element is surface-emitting/receiving and includes a photonic crystal layer.
10 . The device according to claim 8 , wherein the substrate includes Si, InP, or GaAs.
11 . The device according to claim 8 , wherein the substrate includes a lens portion at the second surface.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2021-139049, filed on Aug. 27, 2021; the entire contents of which are incorporated herein by reference. FIELD Embodiments described herein relate generally to an analysis device. BACKGROUND Noninvasive techniques that are used to measure blood substance concentration include optical techniques. When using the mid-infrared wavelength region as in an embodiment of the invention, a higher light source output is required to measure a blood concentration in a blood vessel than to measure a concentration in the tissue fluid of a somatic cell, making it difficult to downsize the light source. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of an analysis device of a first embodiment; FIG. 2A and FIG. 2B are schematic top views of an electrode and a wiring part of the first embodiment; FIG. 3 is a schematic cross-sectional view of an analysis device of a second embodiment; FIG. 4A is a schematic top view of a light detector of the second embodiment, and FIG. 4B is a schematic bottom view of the light detector of the second embodiment; FIG. 5 is a schematic cross-sectional view of an analysis device of a third embodiment; FIG. 6A is a schematic top view of a quantum cascade laser of the third embodiment, and FIG. 6B is a schematic bottom view of a lower surface electrode of the third embodiment; and FIG. 7 is a schematic cross-sectional view of an analysis device of a fourth embodiment. DETAILED DESCRIPTION According to one embodiment, an analysis device includes a substrate including a first surface, and a second surface positioned at a side opposite to the first surface; a light source part located at the first surface of the substrate, the light source part including a quantum cascade laser; a light detector located at the first surface of the substrate; and a wiring part located at the first surface of the substrate, the wiring part being electrically connected with the light source part and the light detector. Embodiments will now be described with reference to the drawings. The same components in the drawings are marked with the same reference numerals. First Embodiment FIG. 1 is a schematic cross-sectional view of an analysis device 1 of a first embodiment. The analysis device 1 includes a substrate 10, a light source part 21, and a light detector 22. The substrate 10 is transmissive to light emitted by the light source part 21. The substrate 10 is, for example, a silicon substrate that includes Si. Or, the substrate 10 may be a compound semiconductor substrate that includes InP or GaAs. The substrate 10 includes a first surface 11 at which the light source part 21 and the light detector 22 are located, and a second surface 12 positioned at the side opposite to the first surface 11. The substrate 10 includes a lens portion 15 at the second surface 12. The lens portion 15 includes a recess, a protrusion, or a periodic structure obtained by patterning the substrate 10. The light source part 21 includes a first quantum cascade laser 21a and a second quantum cascade laser 21b that have different oscillation wavelengths. The first quantum cascade laser 21a and the second quantum cascade laser 21b include, for example, light-emitting layers that include Group III-V compound semiconductors. The light-emitting layers each include a quantum well structure that generates intersubband transitions of carriers; and the light-emitting layers emit light due to intersubband transitions of electrons. The first quantum cascade laser 21a and the second quantum cascade laser 21b each are surface-emitting and include a photonic crystal layer 30. The surface of the light-emitting layer is parallel to the first surface 11 of the substrate 10. The photonic crystal layer 30 includes a two-dimensional diffraction grating. As the two-dimensional diffraction grating, the photonic crystal layer 30 includes, for example, multiple pits arranged periodically in a plane parallel to the first surface 11 of the substrate 10. The light that is emitted by the light-emitting layer resonates due to the photonic crystal layer 30 in directions along the surface of the light-emitting layer and is emitted in a direction that is substantially perpendicular to the first surface 11 of the substrate 10. The substantially perpendicular direction also includes directions tilted in a range that is not less than 2° and not more than 10° with respect to the direction perpendicular to the first surface 11. This surface-emitting structure makes it easy to obtain a high output by increasing the element area. A photonic crystal can be used to realize a surface-emitting quantum cascade laser because the quantum cascade laser generates TM-polarized light. Furthermore, in principle, a quantum cascade laser is capable of high-speed operation and can generate extremely short pulses. The total energy c