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US 2026/0029341 A1Published application
Asymmetric quadrature interferometry for thin film interference suppression in optical photothermal infrared spectroscopy
AssigneePhotothermal Spectroscopy Corp.
InventorsCraig Prater, Derek Decker, David Grigg
Life of this patent
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Abstract
Asymmetric interferometry is used with various embodiments of Optical Photothermal Infrared (OPTIR) systems to suppress thin film interference effects.
Claims21
1-22. (canceled)
A method of operating a photothermal infrared microscope, the method comprising:
- a) illuminating a region of a sample with a pump beam of infrared radiation;
- b) directing probe radiation onto the sample such that the probe radiation at least partially overlaps the region of the sample illuminated by the pump beam of infrared radiation and interacts with at least two surfaces of the sample to create interfering radiation;
- c) collecting the interfering radiation from the sample as collected probe light;
- d) recombining the collected probe light with the probe radiation reflected from a reference reflector to form recombined light;
- e) dividing the recombined light between at least two detectors;
- f) generating detector signals from the at least two detectors;
- and
- g) processing the detector signals in a time domain to generate a composite photothermal signal by performing at least one of:
- (i) peak-to-peak measurement between successive extrema,
- (ii) integrated area measurement within a specified time window, and
- (iii) differential measurement between signal values at specified times.
8 more elements
A photothermal infrared microscope system comprising:
- a pump source configured to illuminate a region of a sample with a pump beam of infrared radiation;
- a probe source configured to direct probe radiation onto the sample such that the probe radiation at least partially overlaps the region of the sample illuminated by the pump beam of infrared radiation and interacts with at least two surfaces of the sample to create interfering radiation;
- collection optics configured to collect the interfering radiation from the sample as collected probe light;
- a reference reflector;
- beam combining optics configured to recombine the collected probe light with the probe radiation reflected from the reference reflector to form recombined light;
- a beam divider configured to divide the recombined light between at least two detectors;
- the at least two detectors configured to generate detector signals;
- and
- a signal processor configured to process the detector signals in a time domain to generate a composite photothermal signal by performing at least one of:
- (i) peak-to-peak measurement between successive extrema,
- (ii) integrated area measurement within a specified time window, and
- (iii) differential measurement between signal values at specified times.
9 more elements
Dependencies are inferred from the claim text.