Thermal diffusion simulations for photothermal oscillators

Abstract

The effect of material parameters on the oscillation amplitude of a photothermal actuator/oscillator was discussed, and a criterion to maximize the amplitude was derived. The bending stress is inversely proportional to the thickness of the irradiated portion, while a certain thickness is necessary for a temperature gradient to be created. Numerical simulations suggested the bending effect becomes largest when the thickness is about the thermal diffusion length of the substance. Experiment using Cu samples with thickness ranging from 0.05 to 0.5mm confirmed the theoretical predictions.