New publication in Optica: Thresholdless deep and vacuum ultraviolet Raman frequency conversion in hydrogen-filled photonic crystal fiber
Long-lived synchronised molecular motion excited in a hydrogen-filled hollow-core fibre can be used for selective frequency conversion of narrowband ultraviolet pulses with efficiencies reaching 60%. This compact system is pressure tunable, uniquely allows for spatial structuring of the out-coupled radiation and performs excellently in the deep and vacuum ultraviolet. All these characteristics are enabled by an optimised ultraviolet guidance and dispersion of the fibre, which features a core diameter of 22 microns and ultrathin core-walls with an average thickness below 100 nm. Interestingly, this novel platform can in principle operate down to the single-photon limit owing to its thresholdless nature, and might enable advances in bio-molecular spectroscopy, where the number of available sources is limited.
Read full publication: M. K. Mridha, D. Novoa, P. Hosseini, and P. St.J. Russell, Optica 6, 731-734 (2019)