A New Type of Apparatus for the Determination of the Thermal Diffusion Factor

conclusions. If a laser giant pulse is sent through the liquid the beam diameter is reduced during its path through the cell due to self-focusing. The diameter at the exit window, which decreases with increasing laser power, follows quasistationarily the instantaneous laser power. For low incident laser power, the diameter increases again after the power has passed its peak value. At high laser power, stimulated Raman scattering in the forward and backward direction and stimulated Brillouin scattering occur, since the self-focused beam diameter is strongly reduced leading to a drastic increase of intensity. These scattering processes in the backward direction attenuate rapidly the laser power and limit the time duration of the self-focusing action.