Generation and Photonic Guidance of Multi-Octave Optical-Frequency Combs
F. Couny,1
F. Benabid,1*
P. J. Roberts,2
P. S. Light,1
M. G. Raymer3
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.
2 Communications, Optics and Materials, Technical University of Denmark, Lyngby, DK-2800, Denmark.
3 Oregon Center for Optics and Department of Physics, University of Oregon, Eugene, OR 97403, USA.
* To whom correspondence should be addressed. E-mail: f.benabid{at}bath.ac.uk
