# US 9,752,927 B2 · Transient grating time resolved luminescence measurements > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,927 B2 - Document ID: US9752927B2 - Status: Granted - Kind: B2 - Application number: 15/117,598 - Filed: 2015-02-05 - Published: 2016-12-08 - Granted: 2017-09-05 - Earliest claimed: 2014-02-10 - Assignees: Victoria Link Limited - Applicants: Victoria Link Ltd - Inventors: Justin M. Hodgkiss; Kai Chen - Web page: https://patentgrep.com/patent/US9752927B2 ## CPC - G01J 1/4228: {arrangements with two or more detectors, e.g. for sensitivity compensation} - G01J 3/0232: {using shutters} - G01J 3/2889: {Rapid scan spectrometers; Time resolved spectrometry} - G01J 3/4406: {Fluorescence spectrometry} - G01N 21/636: {using an arrangement of pump beam and probe beam; using the measurement of optical non-linear properties; (non-linear optics per se G02F1/35)} - G01N 21/6408: {with measurement of decay time, time resolved fluorescence} - G01N 21/65: Raman scattering - G01J 2003/4424: {Fluorescence correction for Raman spectrometry} - G01N 2201/061: Sources - G01N 2201/0696: Pulsed - 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) - 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 A transient grating (TG) is used as an optical gating element with sub-picosecond time resolution for luminescence measurements from a photo-detector array. The transient grating is formed in a gate medium by one or more pulsed gate beams. For photoluminescence measurements such as photoluminescence spectroscopy or imaging, a source is excited by a pulsed excitation beam, and the pulsed gate beams are synchronized to the pulsed excitation beam with an adjustable delay between the excitation of the source and the formation of the TG. Moreover, a source or its spectra can be imaged at two different regions of the photo-detector array at two different times spaced in time by a selected duration of time with sub-picosecond resolution over a range of a nanosecond or more. A beam from the source is deflected to the different regions by changing the frequency or geometry of the pulsed gate beams. ## Claims ### Claim 1 A method of measuring light emitted by a source, said method comprising: (a) imaging light from the source onto a photo-detector array at a selected instant in time by disposing a gate medium between the source and the photo-detector array and also illuminating the gate medium with at least one pulsed gate beam to form a transient grating in the gate medium at the selected instant in time; (b) exciting the source with a pulsed excitation beam, and synchronizing at least one pulsed gate beam to the pulsed excitation beam with an adjustable delay; (c) collecting measurements from the photo-detector array of the light imaged onto the photo-detector array; and (d) repeating the imaging of light from the source onto the photo-detector array and the collecting of measurements from the photo-detector array of the light imaged onto the photo-detector array for different adjusted delays and combining the measurements collected from the photo-detector array to construct a graph of the light imaged from the source as a function of time since the excitation of the source. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein said at least one pulsed gate beam is produced by a femtosecond pulsed laser and the transient grating persists in the gate medium for less than one picosecond so that the measurements collected from the photo-detector array resolve the light imaged from the source with sub-picosecond time resolution. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein the pulsed gate beam is chirped to sweep the imaged light from the source across the photo-detector array. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein the gate medium is configured as an image plate, and the transient grating occupies a fraction of the image plate and sweeps across the image plate. ### Claim 5 (depends on 1) The method as claimed in claim 1, which includes illuminating the gate medium with two or more pulsed gate beams crossing each other in the gate medium to form an interference pattern in the gate medium that induces the transient grating in the gate medium. ### Claim 6 (depends on 1) The method as claimed in claim 1, which includes imaging light at a first instant in time to form a first image of light from the source on a first region of the photo-detector array by forming a first transient grating at the first instant in time in the gate medium, and then imaging light at a second instant in time to form a second image of light from the source on a second region of the photo-detector array by forming a second transient grating at the second instant in time in the gate medium, and comparing the measurements collected from the photo-detector array of the light imaged onto the photo-detector array at the first region to measurements collected from the photo-detector array of the light imaged onto the photo-detector at the second region. ### Claim 7 (depends on 6) The method as claimed in claim 6, which includes splitting a pulsed gate source beam into a first part and a second part, splitting the first part to produce a first gate beam and a second gate beam, and illuminating the gate medium with the first gate beam and the second gate beam at a first crossing angle to produce the first transient grating in the gate medium, and delaying the second part by a selected delay and producing a third gate beam and a fourth gate beam from the delayed second part, and illuminating the gate medium with the third gate beam and the fourth gate beam at a second crossing angle to produce the second transient grating in the gate medium. ### Claim 8 (depends on 6) The method as claimed in claim 6, which includes repeating the imaging of light from the source onto the photo-detector array and the collecting of measurements from the photo-detector array of the light imaged onto the photo-detector array for different adjustable delays between the first instant in time and the second instant in time and the comparing of the measurements collected from the photo-detector array of the light imaged onto the photo-detector array at the first region to measurements collected from the photo-detector array of the light imaged onto the photo-detector array at the second region for different adjusted intervals of time between the first instant in time and the second instant of time, and computing statistics of the measurements. ### Claim 9 (depends on 1) The method as claimed in claim 1, which further includes disposing a polychromator between the source and the photo-detector array so that the light imaged from the source onto the photo-detector array includes a spectrum. ### Claim 10 (depends on 9) The method as claimed in claim 9, wherein the spectrum includes wavelengths of light in the range of ultraviolet to infrared. ### Claim 11 A system for measuring light emitted by a source, said system comprising: (a) a photo-detector array for detecting an image of the light emitted by the source; (b) a gate medium disposed between the source and the photo-detector array so that the image of the light from the source is produced on the photo-detector array when a transient grating is produced in the gate medium; (c) a pulsed gate beam source for producing at least one pulsed gate beam to form the transient grating in the gate medium; (d) a pulsed excitation beam source synchronized to the pulsed gate beam source; and (e) an adjustable delay line for adjusting delay of said at least one pulsed gate beam with respect to the pulsed excitation beam. ### Claim 12 (depends on 11) The system as claimed in claim 11, wherein the gate beam source is a femtosecond pulsed laser and the transient grating persists in the gate medium for less than one picosecond so that the measurements collected from the photo-detector array resolve the light imaged from the source with sub-picosecond time resolution. ### Claim 13 (depends on 11) The system as claimed in claim 11, which includes at least one optical element for splitting a pulsed beam from the gate beam source into two or more pulsed gate beams that cross each other in the gate medium to form an interference pattern in the gate medium that induces the transient grating in the gate medium. ### Claim 14 (depends on 11) The system as claimed in claim 11, wherein the pulsed excitation beam source is a tunable optical parametric amplifier excited by the pulsed gate beam source. ### Claim 15 (depends on 11) The system as claimed in claim 11, wherein said at least one pulsed gate beam produces a first transient grating in the gate medium and a first image of the light from the source on the photo-detector array, and which includes an optical element for splitting the gate beam and an adjustable delay line for producing another pulsed gate beam delayed by a selected duration of time from said at least one pulsed gate beam gate pulse, said another pulsed gate beam being directed to the gate medium to produce a second transient grating in the gate medium, so that the photo-detector array detects a second image of the light emitted by the source, and the second image of the light emitted by the source is located on a different region of the photo-detector array than the first image of the light emitted by the source. ### Claim 16 (depends on 15) The system as claimed in claim 15, which includes a first optical element for splitting said at least one pulsed gate beam into a first part and a second part, a second optical element for splitting the first part to produce a first gate beam and a second gate beam directed to the gate medium at a first crossing angle to produce the first transient grating in the gate medium, and an adjustable delay line for delaying the second part by a selected delay and a third optical element for splitting the delayed second part to produce a third gate beam and a fourth gate beam directed to the gate medium at a second crossing angle to produce the second transient grating in the gate medium. ### Claim 17 (depends on 11) The system as claimed in claim 11, which further includes a polychromator disposed between the source and the photo-detector array so that the light imaged from the source onto the photo-detector array includes a spectrum. ### Claim 18 (depends on 17) The system as claimed in claim 17, wherein the spectrum includes wavelengths of light in the range of ultraviolet to infrared.