title: Self-adjusted all-dielectric metasurfaces for deep ultraviolet femtosecond pulse generation.
abstract: The advantage of metasurfaces and nanostructures with a high nonlinear response is that they do not require phase matching, and the generated pulses are short in the time domain without additional pulse compression. However, the fabrication of large-scale planar structures by lithography-based methods is expensive, time consuming, and requires complicated preliminary simulations to obtain the most optimized geometry. Here, we propose a novel strategy for the self-assembled fabrication of large-scale resonant metasurfaces, where incident femtosecond laser pulses adjust the initial silicon films via specific surface deformation to be as resonant as possible for a given wavelength. The self-adjusting approach eliminates the necessity of multistep lithography and designing, because interference between the incident and the scattered parts of each laser pulse "imprints" resonant field distribution within the film. The self-adjusted metasurfaces demonstrate a high damage threshold (≈1012W cm-2) and efficient frequency conversion from near-IR to deep UV. The conversion efficiency is up to 30-fold higher compared with nonresonant smooth Si films. The resulting metasurfaces allow for the generation of UV femtosecond laser pulses at a wavelength of 270 nm with a high peak and average power (≈105W and ≈1.5 μW, respectively). The results pave the way to the creation of ultrathin nonlinear metadevices working at high laser intensities for efficient deep UV generation at the nanoscale.
authors.affiliation: ITMO University, St. Petersburg 197101, Russia. s.makarov@metalab.ifmo.ru.
authors.forename: S V
authors.initials: SV
authors.lastname: Makarov
authors.affiliation: ITMO University, St. Petersburg 197101, Russia. s.makarov@metalab.ifmo.ru.
authors.forename: A N
authors.initials: AN
authors.lastname: Tsypkin
authors.affiliation: ITMO University, St. Petersburg 197101, Russia. s.makarov@metalab.ifmo.ru.
authors.forename: T A
authors.initials: TA
authors.lastname: Voytova
authors.affiliation: ITMO University, St. Petersburg 197101, Russia. s.makarov@metalab.ifmo.ru.
authors.forename: V A
authors.initials: VA
authors.lastname: Milichko
authors.affiliation: ITMO University, St. Petersburg 197101, Russia. s.makarov@metalab.ifmo.ru and St. Petersburg Academic University, St. Petersburg 194021, Russia.
authors.forename: I S
authors.initials: IS
authors.lastname: Mukhin
authors.affiliation: ITMO University, St. Petersburg 197101, Russia. s.makarov@metalab.ifmo.ru.
authors.forename: A V
authors.initials: AV
authors.lastname: Yulin
authors.affiliation: ITMO University, St. Petersburg 197101, Russia. s.makarov@metalab.ifmo.ru.
authors.forename: S E
authors.initials: SE
authors.lastname: Putilin
authors.affiliation: ITMO University, St. Petersburg 197101, Russia. s.makarov@metalab.ifmo.ru.
authors.forename: M A
authors.initials: MA
authors.lastname: Baranov
authors.affiliation: ITMO University, St. Petersburg 197101, Russia. s.makarov@metalab.ifmo.ru.
authors.forename: A E
authors.initials: AE
authors.lastname: Krasnok
authors.affiliation: St. Petersburg Academic University, St. Petersburg 194021, Russia.
authors.forename: I A
authors.initials: IA
authors.lastname: Morozov
authors.affiliation: ITMO University, St. Petersburg 197101, Russia. s.makarov@metalab.ifmo.ru.
authors.forename: P A
authors.initials: PA
authors.lastname: Belov