Photothermal deflection in multilayer coatings: modeling and experiment

A model of the photothermal deflection signal in multilayer coatings is presented that takes into account optical interference effects and heat flow within the stack. Measurements are then taken of high-reflectivity HfO2/SiO2 ultraviolet mirrors made by plasma ion assisted deposition and compared to calculations. Good agreement is found between the experimental results and the model. Using this model for the calibration and the setup described, one can measure absorption in multilayer coatings accurately down to 10(-7) of the incident power. (c) 2005 Optical Society of America.