Resonant techniques for studying the complex electrodynamic response of conducting solids in the millimeter and submillimeter wave spectral range

In order to study the electrodynamic properties of highly conducting materials in the millimeter and submillimeter wave range, we have developed two resonant techniques which allow us to measure the complex conductivity of metals with unprecedented accuracy. In the frequency range from 8 to 37 cm−1, we employ a Fabry–Perot resonator consisting of a dielectric plate in optical contact with the sample; in the millimeter wave range (1–3 cm−1) the resonant structure is a copper cavity which is perturbed by replacing the endplate by the sample. The purpose of a resonant structure for measuring material parameters is to increase the interaction of the electromagnetic radiation with the material. In so doing, these two resonant structures not only improve the sensitivity of the measurement but also allow for the direct determination of both components of the complex optical parameters of the material.