title: Ultrafast tilting of the dispersion of a photonic crystal and adiabatic spectral compression of light pulses.
abstract: We demonstrate, by theory and experiment, the ultrafast tilting of the dispersion curve of a photonic-crystal waveguide following the absorption of a femtosecond pump pulse. By shaping the pump-beam cross section with a nanometric shadow mask, different waveguide eigenmodes acquire different spatial overlap with the perturbing pump, leading to a local flattening of the dispersion by up to 11%. We find that such partial mode perturbation can be used to adiabatically compress the spectrum of a light pulse traveling through the waveguide.
authors.affiliation: FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.
authors.forename: Daryl M
authors.initials: DM
authors.lastname: Beggs
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Krauss
authors.forename: L
authors.initials: L
authors.lastname: Kuipers
authors.forename: Tobias
authors.initials: T
authors.lastname: Kampfrath