Frequency-comb-referenced quantum-cascade laser at 4.4 microm.

Authors :: Bartalini S
Cancio P
Giusfredi G
Mazzotti D
De Natale P
Borri S
Galli I
Leveque T
Gianfrani L
Source :: Optics letters [Opt Lett] 2007 Apr 15; Vol. 32 (8), pp. 988-90.
Publication Year :: 2007
Abstract: We report what we believe to be the first absolute frequency measurement performed using a quantum-cascade laser (QCL) referenced to an optical frequency comb synthesizer (OFCS). A QCL at 4.43 microm has been used for producing near-infrared radiation at 858 nm by means of sum-frequency generation with a Nd:YAG source in a periodically poled lithium niobate nonlinear crystal. The absolute frequency of the QCL source has been measured by detecting the beat note between the sum frequency and a diode laser at the same wavelength, while both the Nd:YAG and the diode laser were referenced to the OFCS. Doppler-broadened line profiles of (13)CO(2) molecular transitions have been recorded with such an absolute frequency reference.