Excitation and resonant transformation of a surface electromagnetic wave during irradiation of a solid by high-power laser radiation

An analysis is made of the transformation of a surface electromagnetic wave (SEW) into a bulk wave and of the converse process at the corrugated interface of two media. It is shown that the periodic structures (gratings) formed at the surface of a solid exposed to high-power laser irradiation are due to interference between the SEW and the incident wave. Dependences of the diffraction efficiency of the gratings on the average power of the incident radiation were obtained experimentally for bulk samples and thin germanium films. It was found that the complex diffraction pattern observed during irradiation of a surface may be due to resonant interaction between the SEW and the grating. It was demonstrated experimentally that SEW's may be excited and periodic structures may be formed on the surfaces of thin germanium films.