Investigation of Window Materials for High Power CO2 Gas Lasers.

Infrared absorption by multiphonon processes in the transparent regime of solids has been treated by lattice dynamics. Frequency and temperature dependence is predicted and compared with experimental data on alkali halides and alkaline earth fluorides. Effects of molecular impurities in KCl in 10 micrometer region was investigated. The optical properties vibrational and electronic, relevant to high power laser window applications, of amorphous materials has been investigated emphasizing the changes relative to the ordered state resulting from the structural disorder. The temperature, pressure and stress dependence of electronic band gap and the refractive index of several candidate materials are theoretically calculated.