Ricciardi I, De Tommasi E, Maddaloni P, Mosca S, Rocco A, Zondy J-J, De Rosa M, De Natale P
INO–CNR, Istituto Nazionale di Ottica, Sezione di Napoli, and LENS, European Laboratory for Nonlinear Spectroscopy, Via Campi Flegrei 34, I-80078 Pozzuoli (NA), Italy.
Opt Express. 2012 Apr 9;20(8):9178-86. doi: 10.1364/OE.20.009178.
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.
我们展示了一种宽可调谐的单谐振光学参量振荡器，在2.7至4.2μm之间发射功率超过1W，它被锁相到一个自参考频率梳。泵浦频率和信号频率都直接锁相到一个发射近红外光的飞秒锁模光纤激光器的频率梳，该光纤激光器又与铯原子基准相连。我们估计闲频频率在1至200秒之间的分数阿伦偏差约为3×10⁻¹²τ⁻½ 。为了测试光参量振荡器的光谱性能，我们对属于CH₃I的ν1振转带的几个跃迁进行了饱和光谱分析，解析了它们的电子四极超精细结构，估计闲频的半高全宽线宽优于200kHz，并以50kHz的不确定度确定了超精细成分的绝对频率。
