Bistable switching in chalcogenide 1D photonic crystal nanocavities

This paper reports on the first demonstration of high-Q 1D photonic crystal nanocavities in the chalcogenide glass Ge
_11.5
As
₂₄
Se
_64.5
. This material has a high nonlinear figure of merit due to its low two-photon absorption and large Kerr nonlinear coefficient, making it ideal for ultrafast switching applications. The cavity consists of a 1D array of holes in a 580 nm wide waveguide on a silica substrate. The cavity is formed by tapering the size and spacing of the holes in the centre of the PhC to support a mode with calculated intrinsic Q-factor >;106, and volume ~0.7(λ/n)
³
. To achieve high transmission through the cavity at resonance, the number of holes in the mirror was reduced such that the loaded Q-factor is much lower than the intrinsic one.