Photothermal imaging device and system
AssigneeUniversity of Notre Dame du Lac
InventorsZhongming Li, Gregory Hartland, Masaru Ken Kuno
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Abstract
Mid-infrared photothermal heterodyne imaging (MIR-PHI) techniques described herein overcome the diffraction limit of traditional MIR imaging and uses visible photodiodes as detectors. MIR-PHI experiments are shown that achieve high sensitivity, sub-diffraction limit spatial resolution, and high acquisition speed. Sensitive, affordable, and widely applicable, photothermal imaging techniques described herein can serve as a useful imaging tool for biological systems and other submicron-scale applications.
Claims30
A method for detecting infrared light absorption in a sample, the method comprising:
- a) illuminating a region of the sample with a pump beam generated by a first light source, wherein at least a portion of the pump beam is absorbed by the region of the sample;
- b) illuminating the region of the sample with a probe beam generated by a second light source, wherein the probe beam has a wavelength shorter than the pump beam and a Gaussian beam width of less than 2.33 micrometers;
- c) collecting, by a detector, a portion of the probe beam coming from the region of the sample as collected light;
- and
- d) analyzing the collected light to construct a signal indicative of infrared absorption by the region of the sample.
A method for detecting infrared light absorption in a sample, the method comprising:
- a) illuminating a region of the sample with a pump beam generated by a tunable source of mid-infrared radiation, wherein at least a portion of the pump beam is absorbed by the region of the sample at least one wavelength generated by the tunable source of mid-infrared radiation;
- b) illuminating the region of the sample with a probe beam generated by a second light source, wherein the probe beam has a wavelength shorter than the pump beam and a Gaussian beam width of less than 2.33 micrometers;
- c) collecting by a detector at least of a portion of the probe beam coming from the region of the sample;
- d) generating, based on a portion of the probe beam collected by the detector, a signal indicative of an amount of infrared light absorbed by the region of the sample;
- and
- e) repeating (a)-(d) at a plurality of wavelengths of the tunable source of mid-infrared radiation.
A system for detecting infrared light absorption in a sample, the system comprising:
- a first light source operable to illuminate a region of the sample with a pump beam generated by a tunable mid-infrared light source operable to generate radiation at a plurality of wavelengths;
- and wherein the sample absorbs at least a portion of the pump beam at least one wavelength of a tunable light source;
- a second light source operable to illuminate the region of the sample with a probe beam generated by a second light source, wherein the probe beam has a shorter wavelength than that of the pump beam and also has a Gaussian beam width of less than 2.33 micrometers;
- a detector operable to collect at least a portion of the probe beam from the region of the sample;
- and
- a signal processing device configured to generate a signal indicative of an amount of mid-infrared light absorbed by the region of the sample with at the plurality of wavelengths of the tunable IR pump beam.
Dependencies are inferred from the claim text.