Temperature measurement during high-intensity laser-liquid interactions

The interaction of high-intensity, short-pulse laser radiation with liquids is fundamental to many contemporary technologies. Nonlinear phenomena can become important at high intensities, resulting in dramatic changes in the thermal response of the liquid to the incident radiation compared to classical model predictions. This work presents an experimental technique to measure the temperature rise during high-intensity laser-liquid interactions based on photothermal deflection of a laser probe beam. The technique is applicable for both weakly and strongly absorbing liquids, and for moderate and strong focusing of the heating laser beam. The experimental data are compared to theoretical predictions for two distinct high-intensity phenomena: saturable absorption and multiphoton ionization. The agreement between experimental predictions and theoretical results is good.