Eur. Phys. J. Appl. Phys.
Volume 45, Number 2, February 2009
|Number of page(s)||6|
|Section||Instrumentation and Metrology|
|Published online||25 December 2008|
Optoelectronic difference-frequency synthesiser: terahertz-waves for high-resolution spectroscopy
Laboratoire Phlam, UMR 8523 CNRS, 59655 Villeneuve d'Ascq, France
Corresponding author: firstname.lastname@example.org
Revised: 4 November 2008
Accepted: 18 November 2008
Published online: 25 December 2008
We demonstrate a simple approach for a difference-frequency synthesiser within the terahertz domain. Two near-infrared CW diode lasers are frequency-locked to the resonances of a high finesse Fabry-Perot cavity using the Pound-Drever-Hall technique. Two acousto-optic modulators driven by RF synthesizers frequency-shift each diode laser and provide continuous tuning, modulation and switching capabilities for the difference-frequency. Terahertz-waves generated by heterodyne mixing in an ultrahigh-bandwidth photodetector are used to interrogate the rotational transitions in the ground state of the methyl-chloride.
PACS: 42.62.Eh – Metrological applications; optical frequency synthesizers for precision spectroscopy / 33.80.-b – Photon interactions with molecules / 85.60.-q – Optoelectronic devices / 07.57.-c – Infrared, submillimeter wave, microwave and radiowave instruments and equipment
© EDP Sciences, 2008
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