Fig. 1.

Schematic of experimental layout. A pair of modelocked fs lasers, Comb-1 and Comb-2, are actively stabilized to a common cw laser using optical phase-locked loops to enable high-resolution dual-comb spectroscopy of a laser-induced plasma. The laser beams are spatially overlapped on a beamsplitter and simultaneously probe a room temperature Rb cell that serves as a reference spectrum, and a solid ablation target containing trace amounts of Rb and K inside a vacuum chamber. Dashed lines indicate electrical phase-lock feedback loop. PD photodiode, G grating, S slit, M mirror, L lens, C cube beam splitter