LASER EXCITATION OF COUPLED SURFACE ELECTROMAGNETIC AND ACOUSTIC WAVES AND STATIC SURFACE STRUCTURES IN SOLIDS.

The theory is developed of the forced generation of surface waves (SAW) by the action of a single laser beam on absorbing condensed bodies. The SAW instability mechanism is as follows: With the fluctuational appearance of SAW the laser beam wave excites a surface electromagnetic wave, and the interference between this and the laser wave leads to spatially periodic heating of the surface, and consequently to a periodic change in the pressure, which amplifies the fluctuation priming of the SAW. In addition to the normal (Rayleigh) SAW, the dispersion equation obtained also describes the excitation of a new class of SAW - quasi-static induced waves - whose frequency is determined by the intensity of the laser pump. The dependence of the characteristics of the excited SAW on the frequency, polarization and angle of incidence of the laser wave is studied.