Intense few-cycle visible pulses directly generated via nonlinear fibre mode mixing

• Published in: Nature photonics 2021-12, Vol.15 (12), p.884-889
• Main Authors: Piccoli, R., Brown, J. M., Jeong, Y.-G., Rovere, A., Zanotto, L., Gaarde, M. B., Légaré, F., Couairon, A., Travers, J. C., Morandotti, R., Schmidt, B. E., Razzari, L.
• Format: Article
• Language: English
• Subjects: 639/624/1020/1095; 639/624/400/385; Applied and Technical Physics; Compression; Energy; Femtosecond pulses; Gases; Infrared lasers; Lasers; Letter; Light; Photonics; Physics; Physics and Astronomy; Power; Pulse compression; Quantum Physics; Temporal resolution; Ytterbium
• ISSN: 1749-4885; 1749-4893
• DOI: 10.1038/s41566-021-00888-7

Extremely short, high-energy pulses are essential in modern ultrafast science. In a seminal paper in 1996 1 , Nisoli and co-workers demonstrated the first intense pulse compression employing a gas-filled hollow-core fibre. Despite the huge body of scientific work on this technology stemming from ultrafast and attosecond research, here we identify an unexplored few-cycle visible-light generation mechanism, which relies on the nonlinear mixing of hollow-core fibre modes. Using a commercially available ytterbium laser, we generate 4.6 fs, 20 μJ pulses centred at around 600 nm (~2 cycles, ~4 GW peak power), ~40 times shorter than the input 175 fs, 1 mJ pulses at 1,035 nm. Our approach thus directly projects few-hundred-femtosecond-long infrared pulses into the single-cycle regime at visible frequencies, without the need for additional post-compression. As a powerful application of our findings, we present a compact, multicolour pump–probe set-up with a temporal resolution of a few optical cycles. Direct generation of few-cycle high-energy visible pulses is demonstrated via the nonlinear mixing of hollow-core fibre modes. Compression of near-infrared laser pulses by a factor of 40 with no additional dispersion compensation delivers 4.6 fs, 20 μJ pulses (~2 cycles, ~4 GW peak power) centred at around 600 nm.