Abstract
We developed a high-precision spectroscopic system at 8.6 μm based on direct heterodyne detection and phase-locking of a room-temperature quantum-cascade-laser against an harmonic, 250-MHz mid-IR frequency comb obtained by difference-frequency generation. The signal-to-noise ratio of the detected beat-note together with the achieved closed-loop locking bandwidth of allows for a residual integrated phase noise of 0.78 rad (1 Hz–5 MHz), for an ultimate resolution of , limited by the measured linewidth of the mid-IR comb. The system was used to perform absolute measurement of line-center frequencies for the rotational components of the vibrational band of , with a relative precision of .
© 2015 Optical Society of America
Full Article | PDF ArticleMore Like This
Andrew A. Mills, Davide Gatti, Jie Jiang, Christian Mohr, Will Mefford, Livio Gianfrani, Martin Fermann, Ingmar Hartl, and Marco Marangoni
Opt. Lett. 37(19) 4083-4085 (2012)
Kevin Knabe, Paul A. Williams, Fabrizio R. Giorgetta, Michael B. Radunsky, Chris M. Armacost, Sam Crivello, and Nathan R. Newbury
Opt. Express 21(1) 1020-1029 (2013)
Michael G. Hansen, Evangelos Magoulakis, Qun-Feng Chen, Ingo Ernsting, and Stephan Schiller
Opt. Lett. 40(10) 2289-2292 (2015)