title: Generation and photonic guidance of multi-octave optical-frequency combs.
abstract: Ultrabroad coherent comb-like optical spectra spanning several octaves are a chief ingredient in the emerging field of attoscience. We demonstrate generation and guidance of a three-octave spectral comb, spanning wavelengths from 325 to 2300 nanometers, in a hydrogen-filled hollow-core photonic crystal fiber. The waveguidance results not from a photonic band gap but from the inhibited coupling between the core and cladding modes. The spectrum consists of up to 45 high-order Stokes and anti-Stokes lines and is generated by driving the confined gas with a single, moderately powerful (10-kilowatt) infrared laser, producing 12-nanosecond-duration pulses. This represents a reduction by six orders of magnitude in the required laser powers over previous equivalent techniques and opens up a robust and much simplified route to synthesizing attosecond pulses.
authors.affiliation: Department of Physics, Centre for Photonics and Photonic Materials, University of Bath, Bath BA2 7AY, UK.
authors.forename: F
authors.initials: F
authors.lastname: Couny
authors.forename: F
authors.initials: F
authors.lastname: Benabid
authors.forename: P J
authors.initials: PJ
authors.lastname: Roberts
authors.forename: P S
authors.initials: PS
authors.lastname: Light
authors.forename: M G
authors.initials: MG
authors.lastname: Raymer