Spectroscopic applications and frequency locking of THz photomixing with distributed-Bragg-reflector diode lasers in low-temperature-grown GaAs
Abstract
A compact, narrow-linewidth, tunable source of THz radiation has been developed for spectroscopy and other high-resolution applications. Distributed-Bragg-reflector (DBR) diode lasers at 850 nm are used to pump a low-temperature-grown GaAs photomixer. Resonant optical feedback is employed to stabilize the center frequencies and narrow the linewidths of the DBR lasers. The heterodyne linewidth full-width at half-maximum of two optically locked DBR lasers is 50 kHz on the 20 ms time scale and 2 MHz over 10 s; free-running DBR lasers have linewidths of 40 and 90 MHz on such time scales. This instrument has been used to obtain rotational spectra of acetonitrile (CH3CN) at 313 GHz. Detection limits of 1 × 10^–4 Hz^1/2 (noise/total power) have been achieved, with the noise floor dominated by the detector's noise equivalent power.
Additional Information
© 1997 American Institute of Physics. (Received 7 May 1997; accepted 10 July 1997) The authors gratefully acknowledge L. W. Hollberg and S. B. Waltman of the National Institute of Standards and Technology at Boulder, Colorado for their generous assistance on resonant optical feedback.Attached Files
Published - CHEapl97.pdf
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- 2150
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- CaltechAUTHORS:CHEapl97
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2006-03-12Created from EPrint's datestamp field
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2021-11-08Created from EPrint's last_modified field
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- Division of Geological and Planetary Sciences (GPS)