Stimulated Doppler effect on the surface of a gas bubble thermocapillary trapped by a laser in an absorbing liquid

Abstract

A possibility to control the gas bubble size in an absorbing liquid through the laser thermo-capillary trapping has been demonstrated. The coarse structure of the observed interference patterns in reflected and transmitted lights are explained qualitatively within the framework of a two-ray approach. The movement of interference fringes can be treated as manifestation of the Doppler effect because of the moving bubble walls. The method to measure the relative refractive index value for moving contiguous media by means of the Doppler shifts ratio measurement has been proposed. There is a two times discrepancy between Doppler shifts ratio value predicted theoretically and measured in the experiment. It is following from a special stimulated character of the Doppler effect at experimentally realized non-equilibrium thermodynamic conditions, that are imposed by the laser light field.