# US 11,994,465 B2 · Systems and methods for measuring trace contaminants in gas matrix using integrated cavity output spectroscopy > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,994,465 B2 - Document ID: US11994465B2 - Status: Granted - Kind: B2 - Application number: 17/849,395 - Filed: 2022-06-24 - Published: 2023-12-28 - Granted: 2024-05-28 - Earliest claimed: 2022-06-24 - Assignees: ABB Schweiz AG - Applicants: ABB Schweiz AG - Inventors: François Tanguay; Kyle Owen; John Brian Leen; Axel Meunier; Bertrand Simon Lanher - Web page: https://patentgrep.com/patent/US11994465B2 ## CPC - G01N 21/39: using tunable lasers - G01N 21/031: {Multipass arrangements} - G01N 33/225: {Gaseous fuels, e.g. natural gas} - G01J 3/42: Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry (beam switching arrangements G01J3/08) - G01N 21/3151: {using two sources of radiation of different wavelengths (G01N21/33 - G01N21/39 take precedence)} - G01N 21/3504: for analysing gases, e.g. multi-gas analysis - G01N 21/359: using near infrared light - G01N 2021/391: {Intracavity sample} - G01N 2021/399: {Diode laser} - G01N 2201/0612: Laser diodes - G01N 2201/0636: Reflectors - 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) - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) ## Abstract A laser absorption spectrometry system for gas measurement is provided. The system includes an integrated cavity output spectroscopy (ICOS) assembly. The assembly includes a gas cell including a cell body defining an optical cavity, one or more tunable diode lasers having one or more nominal wavelengths, and a reflective collimation mirror positioned in an optical path between the one or more tunable diode lasers and the gas cell. ## Claims ### Claim 1 A laser absorption spectrometry system for gas measurement, comprising: an integrated cavity output spectroscopy (ICOS) assembly comprising: a gas cell comprising a cell body defining an optical cavity; one or more tunable diode lasers having one or more nominal wavelengths; and a reflective collimation mirror positioned in an optical path between the one or more tunable diode lasers and the gas cell, the reflective collimation mirror configured to reduce noise from etalons, wherein when light travels back and forth between parallel surfaces and/or quasi-parallel surfaces in the optical path, the light and its reflection interfere with one another and cause the etalons, the etalons introducing the noise in absorption spectra of the light by gases in the gas cell, wherein the one or more tunable diode lasers comprise a first tunable diode laser configured to emit first laser light in a wavelength range corresponding to a first contaminant in the gases and a second tunable diode laser configured to emit second laser light in a wavelength range corresponding to a second contaminant in the gases. ### Claim 2 (depends on 1) The system of claim 1, wherein the reflective collimation mirror has a parabolic reflection surface. ### Claim 3 (depends on 1) The system of claim 1, wherein the one or more tunable diode lasers include a first tunable diode laser configured to emit first laser light in a first wavelength range in a vicinity of 1574.5 nm. ### Claim 4 (depends on 1) The system of claim 1, wherein the one or more tunable diode lasers include a first tunable diode laser configured to emit first laser light in a wavelength range corresponding to an absorption range of H2S and CO2. ### Claim 5 (depends on 1) The system of claim 1, wherein the one or more tunable diode lasers include a second tunable diode laser configured to emit second laser light in a second wavelength range in a vicinity of 1314 nm. ### Claim 6 (depends on 1) The system of claim 1, wherein the one or more tunable diode lasers include a second tunable diode laser configured to emit second laser light in a second wavelength range corresponding to an absorption range of H2O. ### Claim 7 (depends on 1) The system of claim 1, wherein the one or more tunable diode lasers include a third tunable diode laser configured to emit third laser light in a third wavelength range in a vicinity of 760 nm. ### Claim 8 (depends on 1) The system of claim 1, wherein the one or more tunable diode lasers include a third tunable diode laser configured to emit third laser light in a third wavelength range corresponding to an absorption range of O2. ### Claim 9 A laser absorption spectrometry system for gas measurement, comprising: an integrated cavity output spectroscopy (ICOS) assembly comprising: a gas cell comprising a cell body defining an optical cavity; three or more tunable diode lasers having three or more nominal wavelengths and configured to emit three or more laser light in three or more wavelength ranges, the three or more wavelength ranges corresponding to absorption ranges of three or more different contaminants in gases; and a combiner configured to multiplex the three or more laser light into a combined laser light configured to be coupled into the optical cavity, the combined laser light having the three or more wavelength ranges, wherein the ICOS assembly further comprises a reflective collimation mirror positioned in an optical path between the three or more tunable diode lasers and the gas cell, the reflective collimation mirror configured to reduce noise from etalons, wherein when light travels back and forth between parallel surfaces and/or quasi-parallel surfaces in the optical path, the light and its reflection interfere with one another and cause the etalons, the etalons introducing the noise in absorption spectra of the light by the gases in the gas cell, and wherein the three or more tunable diode lasers comprise a first tunable diode laser configured to emit first laser light in a wavelength range corresponding to a first contaminant in the gases and a second tunable diode laser configured to emit second laser light in a wavelength range corresponding to a second contaminant in the gases. ### Claim 10 (depends on 9) The system of claim 9, wherein the system further comprises a reflective collimation mirror positioned in an optical path between the combiner and the gas cell. ### Claim 11 (depends on 10) The system of claim 10, wherein the reflective collimation mirror has a parabolic reflection surface. ### Claim 12 (depends on 10) The system of claim 10, wherein the combiner includes an optic fiber configured to transmit the combined laser light toward the reflective collimation mirror, the optic fiber having an angled end facing the reflective collimation mirror. ### Claim 13 (depends on 9) The system of claim 9, wherein the three or more tunable diode lasers include a first tunable diode laser configured to emit first laser light in a first wavelength range in a vicinity of 1574.5 nm. ### Claim 14 (depends on 9) The system of claim 9, wherein the three or more tunable diode lasers include a first tunable diode laser configured to emit first laser light in a first wavelength range corresponding to an absorption range of H2S and CO2. ### Claim 15 (depends on 9) The system of claim 9, wherein the three or more tunable diode lasers include a second tunable diode laser configured to emit second laser light in a second wavelength range in a vicinity of 1314 nm. ### Claim 16 (depends on 15) The system of claim 15, wherein the three or more tunable diode lasers include a second tunable diode laser configured to emit second laser light in a second wavelength range corresponding to an absorption range of H2O. ### Claim 17 (depends on 9) The system of claim 9, wherein the one or more tunable diode lasers include a third tunable diode laser configured to emit third laser light in a third wavelength range in a vicinity of 760 nm. ### Claim 18 (depends on 9) The system of claim 9, wherein the three or more tunable diode lasers include a third tunable diode laser configured to emit third laser light in a third wavelength range corresponding to an absorption range of O2. ### Claim 19 (depends on 9) The system of claim 9, wherein the system further comprises a plurality of pumps. ### Claim 20 (depends on 19) The system of claim 19, wherein the system comprises three pumps.