Abstract

Tunable far-infrared (FIR) radiation has been generated using CO₂ laser difference synthesis in metal-insulator-metal diodes either from the difference between a fixed frequency CO₂ laser and a tunable waveguide laser or from the difference between two fixed frequency CO₂ lasers plus microwave sidebands. Our tunable FIR source is being used to make highly accurate FIR frequency measurements of stable species to serve as frequency and wavelength calibration standards, measure frequencies of transient species (including molecular ions) for astronomical searches, and study line broadening and line shape parameters especially for atmospheric spectroscopy applications. The molecules HD, HF, HCI, HBr, CO, NaH, MgH, CH₃OH, ArH⁺, OH, and CH have been studied thus far.

© 1988 Optical Society of America