Ultrafast tilting of the dispersion of a photonic crystal and adiabatic spectral compression of light pulses

TL;DR

This paper demonstrates ultrafast control of photonic crystal dispersion using femtosecond pulses, enabling adiabatic spectral compression of light pulses through mode-specific dispersion tilting.

Contribution

It introduces a novel method of ultrafast dispersion tilting in photonic crystals via spatially shaped pump pulses, achieving spectral compression of light pulses.

Findings

Dispersion curve tilting up to 11% achieved

Spectral compression of light pulses demonstrated

Method combines theory and experimental validation

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.