Open AccessFrequency-comb-referenced singly-resonant OPO for sub-Doppler spectroscopy
Author(s) -
I. Ricciardi,
Edoardo De Tommasi,
P. Maddaloni,
S. Mosca,
A. Rocco,
J.J. Zondy,
M. De Rosa,
P. De Natale
Publication year - 2012
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.009178
Subject(s) - laser linewidth , frequency comb , optics , hyperfine structure , optical parametric oscillator , spectroscopy , rotational–vibrational spectroscopy , doppler effect , laser , physics , comb generator , materials science , atomic physics , excited state , astronomy , quantum mechanics
We present a widely-tunable, singly-resonant optical parametric oscillator, emitting more than 1 W between 2.7 and 4.2 μm, which is phase locked to a self-referenced frequency comb. Both pump and signal frequencies are directly phase-locked to the frequency comb of a NIR-emitting fs mode-locked fibre laser, linked, in turn, to the caesium primary standard. We estimate for the idler frequency a fractional Allan deviation of ∼ 3 × 10⁻¹²τ⁻½ between 1 and 200 s. To test the spectroscopic performance of the OPO, we carried out saturation spectroscopy of several transitions belonging to the ν1 rovibrational band of CH₃I, resolving their electronic quadrupole hyperfine structure, estimating a linewidth better than 200 kHz FWHM for the idler, and determining the absolute frequency of the hyperfine components with a 50-kHz-uncertainty.