Abstract

A number of the most important coherent sources of radiation in the far-IR region of the spectrum derive from pure rotational transitions of gas phase molecular systems. Rotational spectroscopy techniques provide a direct probe of the salient transitions and are consequently a powerful means of obtaining fundamental information about these laser systems. The sensitivity and wide tunability of our submillimeter spectrometer allow us to monitor virtually all states that are involved in the lasing processes. These include states that differ from the lasing states in both vibrational and rotational quantum numbers. This flexibility makes possible the investigation of and differentiation among a number of collisional energy transfer mechanisms. We used these techniques to study both discharge and optically pumped systems.

© 1987 Optical Society of America