THz-TDS with a GHz single-cavity dual-comb laser

We demonstrate THz time-domain spectroscopy (TDS) with a single-cavity dual-comb laser operated at 1 GHz repetition rate. The compact single laser emits two pulse trains with slightly different repetition rates. Due to this condition very rapid and precise optical delay sweeps between two pulse trains are obtained. We show THz-TDS measurements with 1 kHz and 22 kHz delay-sweep rates. Further data processing allows to perform triggerless signal averaging leading to 55 dB dynamic range in the THz spectrum with 2 GHz spectral resolution for a total measurement time of 2 seconds.