The voltage response to pulsed irradiation is calculated with a two-dimensional thermal model that considers localized radiation absorption, thermal boundary resistance, Joule heating, and temperature-dependent properties. A new technique for calculating the voltage response allows the current density, resistivity, and Joule heating distributions to be determined. The calculated voltage response is less than comparable experimental data for a bias current of 1 mA and low temperatures, but agrees with the data for 5 mA bias current. The voltage response is shown to decrease strongly with increasing film thickness and irradiation wave number.