# US 11,313,667 B2 · Methods for the stabilization of interferometric systems and interferometric systems implementing such methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,313,667 B2 - Document ID: US11313667B2 - Status: Granted - Kind: B2 - Application number: 16/987,957 - Filed: 2020-08-07 - Published: 2021-02-11 - Granted: 2022-04-26 - Earliest claimed: 2019-08-09 - Assignees: LightOn - Applicants: LightOn SAS - Inventors: Kilian Müller; Laurent Daudet; Igor Carron; Gustave Pariente - Web page: https://patentgrep.com/patent/US11313667B2 ## CPC - G01B 9/02028: {Two or more reference or object arms in one interferometer} - G06E 3/005: {using electro-optical or opto-electronic means} - G01B 9/02007: {Two or more frequencies or sources used for interferometric measurement (using only beat G01B9/02003)} - G01B 9/02057: {by using common path configuration, i.e. reference and object path almost entirely overlapping} - G01B 9/02072: {by calibration or testing of interferometer} - G01N 21/45: using interferometric methods; using Schlieren methods - G01N 2201/1211: for temperature - G01N 2201/1214: for humidity - G01N 2201/1218: for pressure variations - G06N 3/0675: {using electro-optical, acousto-optical or opto-electronic means} - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G06E: OPTICAL COMPUTING DEVICES (digital storage using optical elements G11C13/04) - 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) - G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS ## Abstract The present description relates to a stabilized interferometric system comprising: a light source (210) for emitting an initial beam of coherent light; a spatial light modulator (220) configured to receive at least a first part of said initial beam and input data (203) and configured to emit a spatially modulated beam resulting from a spatial modulation of a parameter of said first part of said initial beam based on said input data; a scattering medium (230) configured to receive said spatially modulated beam; a detection unit (240) configured to acquire an interference pattern (IN0) resulting from the interferences between randomly scattered optical paths taken by the spatially modulated beam through the scattering material; a control unit (250) configured to vary the frequency of the laser source in order to at least partially compensate a change in said interference pattern resulting from a change in at least one environmental parameter. ## Claims ### Claim 1 A stabilized interferometric system comprising: a light source for emitting an initial beam of coherent light; a spatial light modulator configured to receive at least a first part of said initial beam and input data, and configured to emit a spatially modulated beam resulting from a spatial modulation of a parameter of said first part of said initial beam based on said input data; a scattering medium configured to receive said spatially modulated beam; a detection unit configured to acquire an interference pattern in a first detection plane at an output of said scattering material, wherein said interference pattern results from the interferences between randomly scattered optical paths taken by the spatially modulated beam through the scattering material; and acquire a reference interference pattern in said first detection plane; the reference interference pattern resulting from the interferences between randomly scattered optical paths taken by a reference beam through the scattering material; and a control unit configured to vary the frequency of the light source as a function of a change in said reference interference pattern in order to at least partially compensate a change in said interference pattern resulting from a change in at least one environmental parameter, wherein varying the frequency of the light source comprises: calculating a measurement of similarity between two interference patterns corresponding to said reference interference pattern acquired at two different times; determining a variation of the frequency to apply to the light source based on said measurement of similarity. ### Claim 2 (depends on 1) The stabilized interferometric system of claim 1, wherein said reference beam results from a spatial modulation of a parameter of said first part of said initial beam based on a reference digital input signal. ### Claim 3 (depends on 1) The stabilized interferometric system of claim 1, further comprising a reference optical detector configured to acquire said reference interference pattern resulting from the interferences between randomly scattered optical paths taken by a reference beam through the scattering material, wherein said reference beam is generated by a second part of said initial beam directly sent to said scattering medium. ### Claim 4 (depends on 1) The stabilized interferometric system of claim 1, further comprising: an environmental sensor configured to monitor at least one environmental parameter; and wherein the control unit is configured to vary the frequency of the light source as a function of a change in a measure of said at least one environmental parameter. ### Claim 5 (depends on 1) The stabilized interferometric system of claim 1, wherein the scattering medium is a multiple scattering medium. ### Claim 6 A method for stabilization of an interferometric system, wherein said interferometric system comprises: a light source for emitting an initial beam of coherent light; a spatial light modulator configured to receive at least a first part of said initial beam and input data, and configured to emit a spatially modulated beam resulting from a spatial modulation of a parameter of said first part of said initial beam based on said input data; a scattering medium configured to receive said spatially modulated beam; a detection unit configured to acquire an interference pattern in a first detection plane at an output of said scattering medium, wherein said interference pattern results from the interferences between randomly scattered optical paths taken by the spatially modulated beam through the scattering medium; wherein the method comprises: acquiring, using said detection unit, a reference interference pattern in said detection plane, wherein said interference pattern results from the interferences between randomly scattered optical paths taken by a reference beam through the scattering medium; varying the frequency of the light source as a function of a change in said reference interference pattern in order to at least partially compensate a change in said interference pattern resulting from a change in at least one environmental parameter; wherein varying the frequency of the light source comprises calculating a measurement of similarity between two interference patterns corresponding to said reference interference pattern acquired at two different times; and determining a variation of the light source frequency to apply to the light source based on said measurement of similarity. ### Claim 7 (depends on 6) The method for stabilization of claim 6, further comprising spatially modulating a parameter of said first part of said initial beam using a reference digital input signal to generate said reference beam. ### Claim 8 (depends on 6) The method for stabilization of claim 6, wherein: the reference interference pattern is acquired using a reference optical detector, and wherein said reference beam is generated by a second part of said initial beam directly sent to said scattering medium. ### Claim 9 (depends on 6) The method for stabilization of claim 6, further comprising: monitoring, using an environmental sensor, at least one environmental parameter; and wherein varying the frequency of the light source is made as a function of a change in a measure of said at least one environmental parameter. ### Claim 10 (depends on 6) The method for stabilization of claim 6, wherein a parameter of said first part of said initial beam spatially modulated is the amplitude, the intensity, the phase and/or the polarization of the initial beam. ### Claim 11 (depends on 6) The method for stabilization of claim 6, wherein the scattering medium is a multiple scattering medium.