New photothermal deflection technique to discriminate between heating and cooling

Publication date: January 2018
Source:Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 204
Author(s): Ross S. Fontenot, Veerendra K. Mathur, John H. Barkyoumb
Photothermal deflection spectroscopy (PDS) is a highly sensitive and precise technique that is used to measure the optical absorption and thermal characteristics of a sample. While most applications of PDS utilize a heating beam, laser cooling of solids, or optical refrigeration as it is sometimes called, use this technique to determine if a laser is cooling or heating a sample. Current PDS methods for laser cooling require multiple laser wavelengths in both the Stokes and anti-Stokes region to ensure that cooling is occurring. This can cause problems if lasers must be changed or no lasers in the desired wavelength are available. Herein, we present a photothermal deflection technique that uses the deflection of the probe laser to determine if microcooling is occurring inside a sample.



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