Optical Characterization of Thin Metallic and Semiconducting Films in the Far Infrared

Abstract

The performance in a cw optically pumped far infrared (fir) laser of a hybrid metal mesh-dielectric mirror consisting of an assembly of thin metallic and semiconducting films is evaluated. Its construction is described and an overview of theoretical approaches predicting its optical properties is outlined. From the general model which best agrees with the experimentally determined transmission a simplified model is derived and shown to maintain sufficient accuracy to warrent its further utilization.

Ultra-thin semiconducting heterostructures are also examined using fir techniques. In particular, it is shown that by fitting a calculated reflectivity based on a simple classical model to the fir reflectivity obtained experimentally, both electrical (free carrier concentration, mobility) and lattice (polar phonon frequencies) parameters can be obtained with reasonable accuracy.