A generalized thermal model for laser damage in infrared detectors

Abstract

Four previously published models for laser damage in infrared detectors, based on closed-form solutions to the heat diffusion equation, are reviewed and their limitations discussed. A generalized two-dimensional numerical model based on a finite element technique is presented. This model can be used to calculate damage thresholds whenever the closed-form solutions are not appropriate, and is sufficiently general that it can treat most cases expected to be of interest in laser detector damage. The numerical model is used to calculate thresholds for HgCdTe photovoltaic detectors. Experimentally measured laser damage thresholds are reported for Hg0.8Cd0.2Te crystals whose size and thermal configurations are similar to those of photovoltaic detectors. These thresholds are found to be in good agreement with theoretical values.