INTERACTION OF IR LASER-RADIATION WITH PERIODIC METAL-SURFACES

The interaction of MIR radiation with periodic metal surfaces is studi ed. The TEA-CO2 laser and optoacoustic method of measuring surface-abs orbed energy are used. The main emphasis is placed on studies of the i nfluence of resonant excited surface electromagnetic waves (SEW) on ab sorption, reflection and radiation of IR. The sharp peaks in absorptio n and spectral emissivity, corresponding to resonant SEW excitation, a re observed. Resonant absorption exceeds the background one by more th an two orders of magnitude. The influence of the relief depth and shap e on the magnitude and angular dependence of resonance absorption is s tudied. It is shown that without resonant SEW excitation the absorptio n and the radiation of ''shallow'' gratings is described by Fresnel fo rmulas. The influence of angular and frequency spectra of radiation on the magnitude an angular dependence of the resonance absorption and t he radiation coefficient is studied. It is found that with an increase of the widths of the angular and frequency spectra, absorption is dec reased and the widths of Wood's anomalies are increased. The fine stru cture of a specular reflected beam is discovered. It has been shown th at the analytical theory is in a qualitative agreement with the experi mental results.