Feed-forward coherent link from a comb to a diode laser: Application to widely tunable cavity ring-down spectroscopy.
J Chem Phys
; 148(5): 054202, 2018 Feb 07.
Article
em En
| MEDLINE
| ID: mdl-29421905
ABSTRACT
We apply a feed-forward frequency control scheme to establish a phase-coherent link from an optical frequency comb to a distributed feedback (DFB) diode laser This allows us to exploit the full laser tuning range (up to 1 THz) with the linewidth and frequency accuracy of the comb modes. The approach relies on the combination of an RF single-sideband modulator (SSM) and of an electro-optical SSM, providing a correction bandwidth in excess of 10 MHz and a comb-referenced RF-driven agile tuning over several GHz. As a demonstration, we obtain a 0.3 THz cavity ring-down scan of the low-pressure methane absorption spectrum. The spectral resolution is 100 kHz, limited by the self-referenced comb, starting from a DFB diode linewidth of 3 MHz. To illustrate the spectral resolution, we obtain saturation dips for the 2ν3 R(6) methane multiplet at µbar pressure. Repeated measurements of the Lamb-dip positions provide a statistical uncertainty in the kHz range.
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MEDLINE
Idioma:
En
Revista:
J Chem Phys
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Itália