Application of submillimetre waveguide lasers to the study of absorption in elemental amorphous solids

Optically pumped molecular gas lasers are useful sources of submillimetre (SMM) waves for spectroscopic investigations of solids, particularly in cases where the required spectroscopic resolution is such that continuous tuning is unnecessary. The molecular gas laser, which may be of the conventional or the waveguide design and run in either a pulsed or a cw mode, privides an intense (by spectroscopic standards), monochromatic source whose tuning capabilities are restricted only by the availability of different laser lines. Over the spectral region from about 10 to 100 cm^-1 (0.1-1.0 mm) a resolution of 3 cm^-1 can generally be obtained by employing known laser lines from a number of different gases. A molecular gas laser is particularly useful for spectroscopic investigations of the far-infrared, dielectric properties of amorphous solids because the resolution required is never less than ~ 5cm^-1. In the hope that the details of the far-infrared absorption processes in amorphous solids can be best understood by examining the simplest materials, we have investigated the absorption (or dielectric loss) in three elemental amorphous solids. Se, As and Ge, whose local coordination numbers are 2, 3 and 4, respectively. © 1978.