Subterahertz BWO spectroscopy: methods and devices

Modern sub-terahertz (subTHz) spectrometers, based on coherent sources of radiation, the backward-wave oscillators (BWOs), are described which cover the frequencies V=1 cm/sup -1/-48 cm/sup -1/ (30-1450 GHz) and allow for measurements at temperatures 2-1000 K, also in magnetic fields. They allow for direct determination of spectra of any optical parameter of a material at millimeter-submillimeter wavelengths, the domain where infrared or microwave spectrometers encounter serious methodological difficulties. We report on new technical abilities of the quasioptical BWO-spectrometers and discuss their main components.