Laser-Induced Reflectance Transient Gratings Method : Photothermal and photoacoustic phenomena investigated for films and media interface by the dynamical gratings technique

The results of theoretical and experimental studies of thermal and acoustic gratings excited at two media interface have been presented in the work. One medium is highly absorbing substance whereas another is transparent one at the spectral range of excitation and probing beams used. All the investigations have been conducted under reflecting configuration of probe beam. Aim of the work is to elaborate and experimentally implement the methods for thermal characterization and temperature remote sensing of metal and narrow band gap semiconductor surfaces, thin films as well as adjacent transparent gases and liquids. In-plane thermal diffusivity of nanocrystalline diamond film on substrate has been measured for the first time. It has been shown that in order to minimize the substrate influence on the results of measurements the grating spacing should be as small as comparable to film thickness. The sensivity of diffracted beam detection have to be increased at the same time. Method of out-of-plane thermal diffusivity of thin dielectric films that are transparent in spectral range used has been proposed and tested under modeling condition. It has been experimentally...