2019/06/09 by N. Picqué, Nathalie Picqué, Theodor W. Hänsch · 1 citation
Chemistry · Physics and Astronomy · #Advanced Fiber Laser Technologies #Laser-Matter Interactions and Applications #Spectroscopy and Laser Applications #physics.atom-ph #physics.chem-ph #physics.optics #quant-ph
paper · pdf · doi:10.1073/pnas.2010878117
published as Proceedings of the National Academy of Sciences of the United States of America 117, 26688-26691 (2020) · 9 pages, 3 figures
arxiv created 2019/06/09 · openalex publication_date 2020/10/14 · arxiv updated 2020/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
We demonstrate single-photon time-domain interference in a new realm. We observe interferences in the photon counting statistics with two separate mode-locked femtosecond lasers of slightly different repetition frequencies, each emitting a comb of evenly spaced spectral lines over a wide spectral span. We exploit the interference pattern for spectroscopic diagnostics over a broad spectral range. An experimental proof-of-concept shows that the emerging technique of high-resolution dual-comb Fourier transform spectroscopy can be performed at light powers that are a billion-fold weaker than those commonly employed. Our experiments challenge the intuitive concept that a photon exists before detection and they open the prospect of precise spectroscopy over broad spectral bandwidth in light-starved conditions.