Determinación de propiedades térmicas y ópticas en sólidos mediante la técnica Fotoacústica: Consideración de una fuente de calor periódica cuadrada

Abstract

This thesis work presents a mathematical model for the Photoacoustic signal, which provides a general formulation of the amplitude modulation for the power density of the optical excitation, which ensures greater consistency of the model with experimental arrangements typically used in the Photoacoustic technique. This model generalizes the model developed by Rosenwaig and Gersho, and models until now based on it. As part of the mathematical construction of the model, a more precise criterion for the definition of regimes thermally thick and thermally thin is derived from it. The developed model is used to generate useful functions in fitting processes by non-linear least squares, validated through the determination of the thermal diffusivity for conductor and semiconductor material samples. Finally, on the situation of characterization of crystalline semiconductor materials, a much simpler model for the Photoacoustic signal is obtained, which allows the determination of parameters of electronic transport.