Chemical mapping using thermal microscopy at the micro and nano scales

A method for photo-thermal spectroscopic imaging, comprising:

• using an infrared laser to photo-thermally heat a sample in a confocal setup and
• measuring the resulting increase in thermal emissions using a laser probe comprising an ultraviolet or visible laser reflected from the sample,
• wherein the method is non-contact, and
• wherein the reflected signal from the visible probe is detected using an interferometry setup to maximize the weak signal due to small sample movement during heating.

A method for photo-thermal spectroscopic imaging, comprising:

• using an infrared laser to photo-thermally heat a sample in a confocal setup and
• measuring the resulting increase in thermal emissions using a laser probe comprising an ultraviolet or visible laser reflected from the sample,
• wherein the method is non-contact, and
• wherein the reflected signal from the visible probe is detected using an interferometry setup and wherein either a moving mirror arm of the interferometer or the sample are dithered at a higher frequency than the periodic heating to eliminate a varying photo-thermal signal.