The method of photothermal beam deflection was demonstrated for measuring the absorption spectrum of an aqueous Nd<sup>3+</sup> solution at temperatures between 25°C and 90°C. Changes in the magnitude of the observed deflection can be correlated with the temperature dependence of both the absorptivity of the Nd<sup>3+</sup> ions and the physical properties of the solvent, most notably the thermo-optic coefficient d<i>n</i>/d<i>T</i>.
Jonathan D. Spear, Robert J. Silva, Gregory L. Klunder, and Richard E. Russo, "Collinear Photothermal Deflection Spectroscopy of Liquid Samples at Varying Temperature," Appl. Spectrosc. 47, 1580-1584 (1993)