Near-Ultraviolet Frequency-Agile Dual-Comb Spectroscopy

Dual-comb spectroscopy [1] has emerged as a powerful tool for broad-spectral-bandwidth spectroscopy in the near-infrared and mid-infrared spectral regions. Exploring the ultraviolet spectral region will enable to reach electronic transitions in atoms and rovibronic transitions in molecules. Here, we demonstrate frequency-agile dual-comb spectroscopy [2], [3] in the near-ultraviolet region. Our dual-comb spectra exhibit a signal-to-noise ratio at the quantum limit, a comb line spacing and a center frequency which can be chosen by dialing a knob. We further show that photon-counting dual-comb spectroscopy [4] is a powerful approach for further extension at shorter wavelengths.