EMISSION FREQUENCY OF THE 496 um LINE IN $12CH_{3}F$ AS A FUNCTION OF PRESSURE AND PUMP OFFSET BY INFRARED-SUBMM DOUBLE RESONANCE TECHNIQUES
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Date
1988
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Ohio State University
Abstract
The frequency accuracy and reproducibility of OPFIR lasers is important to their application as local oscillators in heterodyne systems and as primary frequency sources in spectroscopy. We have employed an infrared-submm double resonance technique to investigate the gain frequency as a function of both pressure and pump offset. The interpretation of our experiment is greatly simplified by the absence of cavity pulling and other effects associated with an oscillating laser. The submm probe was obtained from a harmonic multiplier driven by a phase locked klystron; the pump beam was produced by a tunable waveguide $CO_{2}$ laser. To first approximation the FIR gain peak linearly tracks the IR pump offset; this is consistent with a theory in which the cross section for state changing collisions greatly exceeds the cross section for velocity changing collisions. We have previously reported pressure broadening parameters for a variety of transitions within the V3 excited vibrational state of this species; the implications of those results to the question of pressure shift will be discussed.
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Author Institution: Department of Physics, Duke University; Army Research Office, Research Triangle Park; Department of Physics, Duke University