# US 2014/0191131 A1 · Terahertz Wave Generator and Terahertz Wave Measurement Method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191131 A1 - Document ID: US20140191131A1 - Status: Published application - Kind: A1 - Application number: 14/146,892 - Filed: 2014-01-03 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: ARKRAY, Inc. - Applicants: Arkray, Inc. - Inventors: Hirohisa Uchida; Naoto Shichi - Web page: https://patentgrep.com/patent/US20140191131A1 ## CPC - G02F 1/3544: {Particular phase matching techniques} - G01N 21/3581: using far infrared light; using Terahertz radiation - G02F 1/3534: {Three-wave interaction, e.g. sum-difference frequency generation (G02F1/3532 takes precedence)} - G02F 1/3503: {Structural association of optical elements, e.g. lenses, with the non-linear optical device} - G02F 1/3507: {Arrangements comprising two or more nonlinear optical devices} - G02F 2203/13: involving THZ radiation - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract Excitation light of two wavelengths is incident to an optical crystal from a first face side, and a terahertz wave THzb is generated from a second face, and the excitation light that has passed through the optical crystal is reflected, made incident to the optical crystal from the second face side, and a terahertz wave THza is generated from the first face. Terahertz waves with similar characteristics to each other are thereby generated reliably in plural directions. ## Claims ### Claim 1 A terahertz wave generator comprising: a nonlinear optical crystal that is disposed on an optical path of excitation light containing light with a plurality of different wavelength components, and that generates a terahertz wave by difference frequency generation based on the incident excitation light; and a plurality of detectors that detect each of terahertz waves generated in a plurality of directions from the nonlinear optical crystal. ### Claim 2 (depends on 1) The terahertz wave generator of claim 1, wherein: the excitation light is made incident in a direction from a first face of the nonlinear optical crystal towards a second face on an opposite side from the first face, the excitation light that has passed through the nonlinear optical crystal is made incident in a direction from the second face towards the first face, and terahertz waves are respectively generated from the first face and the second face by collinear phase matching. ### Claim 3 (depends on 2) The terahertz wave generator of claim 2, further comprising: an excitation light generator that is equipped with a first mirror and a second mirror that together with the first mirror configures an oscillator, and that generates the excitation light. ### Claim 4 (depends on 2) The terahertz wave generator of claim 2, further comprising: a pair of off-axis parabolic mirrors that each comprise a pass-through portion through which excitation light passes and a reflection face that reflects incident terahertz waves, and that are each disposed so as to reflect the incident terahertz waves, wherein the nonlinear optical crystal is disposed between the pair of off-axis parabolic mirrors. ### Claim 5 (depends on 2) The terahertz wave generator of claim 2, wherein the nonlinear optical crystal has a shape with at least two flat faces. ### Claim 6 (depends on 1) The terahertz wave generator of claim 1, wherein the nonlinear optical crystal has a shape with at least a first flat face and a second flat face on an opposite side from the first flat face, and terahertz waves are generated in a plurality of directions by Cherenkov phase matching by making the excitation light incident from a side face of the nonlinear optical crystal. ### Claim 7 (depends on 6) The terahertz wave generator of claim 6, further comprising: an excitation light generator that is equipped with a first mirror and a second mirror that together with the first mirror configures an oscillator, and that generates the excitation light. ### Claim 8 (depends on 6) The terahertz wave generator of claim 6, further comprising a guide-wave body that is provided at at least one of the first flat face or the second flat face of the nonlinear optical crystal and that guides a terahertz wave generated from the nonlinear optical crystal in a direction according to a generation direction. ### Claim 9 (depends on 1) The terahertz wave generator of claim 1, wherein the nonlinear optical crystal is plate shaped. ### Claim 10 (depends on 1) The terahertz wave generator of claim 1, further comprising a placement section for placing a sample on at least one optical path of a generated terahertz wave. ### Claim 11 (depends on 1) The terahertz wave generator of claim 1, wherein each of the plurality of detectors is an imaging apparatus for capturing an image according to intensity of a generated terahertz wave. ### Claim 12 (depends on 1) A terahertz wave measurement method comprising, in the terahertz wave generator of claim 1: illuminating the excitation light onto the nonlinear optical crystal; illuminating at least one out of terahertz waves generated in a plurality of directions from the nonlinear optical crystal onto a sample; and using the detectors to detect a terahertz wave that has passed through the sample or been reflected by the sample, or to directly detect a generated terahertz wave. ### Claim 13 (depends on 12) The terahertz wave measurement method of claim 12, wherein terahertz waves generated from the nonlinear optical crystal in a plurality of directions are illuminated onto at least one of a measurement sample or a reference sample. ### Claim 14 (depends on 13) The terahertz wave measurement method of claim 13, wherein one of the terahertz waves generated from the nonlinear optical crystal in the plurality of directions is illuminated onto the measurement sample, and another of the terahertz waves is illuminated onto the reference sample. ### Claim 15 (depends on 13) The terahertz wave measurement method of claim 13, wherein each of the terahertz waves generated from the nonlinear optical crystal in the plurality of directions are illuminated onto different measurement samples or reference samples.