US 12,276,603 B2
Asymmetric interferometric optical photothermal infrared spectroscopy
Craig Prater, Santa Barbara, CA (US); David Grigg, Santa Barbara, CA (US); and Derek Decker, Carmel, CA (US)
Assigned to Photothermal Spectroscopy Corp., Santa Barbara, CA (US)
Filed by Photothermal Spectroscopy Corp., Santa Barbara, CA (US)
Filed on Aug. 18, 2023, as Appl. No. 18/452,023.
Application 18/452,023 is a continuation of application No. 17/955,131, filed on Sep. 28, 2022, granted, now 11,774,354.
Application 17/955,131 is a continuation of application No. 16/702,094, filed on Dec. 3, 2019, granted, now 11,480,518, issued on Oct. 25, 2022.
Prior Publication US 2024/0044782 A1, Feb. 8, 2024
Int. Cl. G01J 3/45 (2006.01); G01N 21/35 (2014.01); G02B 21/00 (2006.01)
CPC G01N 21/35 (2013.01) [G01J 3/45 (2013.01); G02B 21/002 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A method for microscopic analysis of a sample to provide improved characterization of infrared absorption of the sample, the method comprising:
illuminating the sample with a beam of mid-infrared radiation to create an infrared illuminated spot on the sample;
illuminating the sample with a beam of probe radiation at least partially overlapping the infrared illuminated spot;
collecting probe light from the sample,
interfering, with an asymmetric interferometer, the collected probe light with a reference beam to create interfering radiation,
collecting the interfering radiation at at least one detector,
analyzing the detected interfering radiation to produce a signal indicative of mid-infrared absorption of the sample.