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Updated: Sep 13, 2025

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
Lamb-dip spectroscopy of rotational levels with photomixing terahertz emitter
Abstract:
Terahertz transmission and Lamb-dip spectroscopy were performed on the (J, K) = (16, 0) ← (15, 0) rotational transition of acetonitrile molecules. By systematically varying the sample pressure and irradiation intensity, we determined the saturation intensity and homogeneous linewidth, both of which show excellent agreement with predictions from a two-level model. In the zero-pressure limit, the homogeneous linewidth was estimated to be 10 kHz, attributed to transit-time broadening. A frequency accuracy of 10-9 was achieved, comparable to the best results previously reported using Lamb-dip spectroscopy in the sub-terahertz regime. These results will open the door to compact, high-precision molecular clocks based on sub-terahertz Lamb-dip spectroscopy.
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