High-sensitivity spectroscopy in the mid-infrared with a single-cavity dual-comb OPO

We present a novel detection scheme for high-sensitivity spectroscopy in the mid-infrared. We use a low-noise and low-complexity dual-comb source based on a PPLN OPO and an Yb:YAG pump. Both the laser and OPO are spatially-multiplexed single-cavity dual-comb sources. At a repetition rate of 250 MHz and ps-long pump pulses, high power per comb line of >120 W is achieved at 3000 nm (idler). The idler is tunable from 2700 nm to 5170 nm. The system enables comb-line-resolved dual-comb spectroscopy measurements in free-running operation. With our detection scheme, we achieve a spectral coefficient SNR/√τ > 10000 √Hz (40 dB) at 3 µm.