Determination of temperature dependence of platinum absorptivity via surface electromagnetic wave attenuation measuring

Measurements of surface electromagnetic wave (SEW) attenuation coefficient alpha dependence from temperature T for platinum have been made. The SEW excitation was produced by CO₂ laser radiation ( lambda = 10.6 mum) on diffraction grating, when first, diffraction order propagation direction was along the platinum mirror surface. In the temperature range 20-100 degC the attenuation coefficient derivative beta = dalpha/dT = (18plusmn2)times10^-4 cm ^-10C^-1 was obtained. From these measurements the platinum absorptivity A temperature derivative dA/dT = 2.7times10^-50C^-1 was obtained. Together with SEW excitation an excitation of near surface bulk wave (NSBW), propagating from diffraction grating at the grazing angle 2.5deg to mirror surface, was observed. It was shown that the NSBW was caused by laser radiation divergence