Photoacoustic spectroscopy: A tool for optical properties study

In photoacoustic spectroscopic (PAS) technique, acoustic piston model is considered and the optical properties of solids are studied. One has to detect the photoacoustic (PA) signal produced when a sample placed in a cell is irradiated by an intensity modulated beam of light. The PA signal is used to investigate the optical properties of solids. In this paper we report on the theoretical, experimental issues on the application of photoacoustic spectroscopy for the investigation of optical properties of Cu2GeSe3 compound. Optical-absorption spectra has been obtained in the range of 0.76 -0.81 eV photon-energy at temperatures between 70 and 300 K. The thermal variation of band-gap energy has been estimated from the optical-absorption spectra at different temperatures.