Bond-selective transient phase imaging via sensing of the infrared photothermal effect

摘要

The probe light passes through the sample and interferes with the reference beam at the camera. A phase image of the sample is then retrieved based on the interferogram. Next, IR pulses at the sample induce vibrational absorption (point A) and thus a local temperature increase that changes the local optical phase shift compared to that of point B, which has no absorption peak at this wavelength. The transient change in phase shift is then obtained by subtraction between the adjacent hot and cold phase frames. By tuning the IR frequency , the spectroscopy at each pixel can be acquired.