Abstract

The capabilities of the photoacoustic technique to measure small absorptivities is now well documented. This capability is now being exploited to measure nonlinear absorption in a variety of materials. The potentials of this new non-linear spectroscopic techniques are just beginning to be realized. Preliminary experiments have shown the ability to separate linear and nonlinear absorption in solids,¹ several nonlinear processes in gases have been observed,² and Raman and two-photon spectra of liquids have been obtained.^3,4 All indications are that nonlinear photoacoustic spectroscopy, NLPAS, will be as fruitful a field as linear photoacoustic spectroscopy has been in the past.

© 1981 Optical Society of America