Development of GaAs Infrared Window Material

摘要

The choice of a window material suitable for high power CO2 lasers emitting at 10.6 microns is discussed. Gallium arsenide was chosen as the primary candidate with gallium antimonide being the object of a subsidiary investigation. The preparation of GaAs is discussed at length. The physical, electrical and optical properties of GaAs are also discussed with particular reference to the high-resistivity form which is necessary to reduce free-carrier absorption at 10.6 microns to an acceptable level. The method used to measure the optical absorption coefficient is a calorimetric one making use of a low power CO2 laser. The variation of the optical absorption coefficient with impurities, different dopants, resistivity, laser beam polarization and various growth parameters is examined. Techniques for preparing material in sizes considerably larger than prior state-of-the-art were developed. (Author)