Dual-frequency-comb UV spectroscopy with one million resolved comb lines

We present high-resolution dual-comb spectroscopy across two broad UV spectral regions spanning 372-410 nm and 325-342 nm. This is achieved by generating sixth and seventh harmonics, respectively, from a low-noise 2.35 mu m Cr:ZnS dual-comb laser system. The sixth harmonic band contains approximately 1,000,000 spectrally resolved comb lines, while the seventh harmonic band-around 550,000 comb lines. With the line spacing of 80 MHz, this corresponds to a resolving power of up to 10 million, offering remarkable spectral resolution. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement