Interplay of plasma-induced and fast thermal nonlinearities in a GaAs-based photonic crystal nanocavity

We investigate the nonlinear response of GaAs-based photonic crystal cavities at time scales which are much faster than the typical thermal relaxation rate in photonic devices. We demonstrate a strong interplay between thermally and carrier-induced nonlinear effects. We have introduced a dynamical model entailing two thermal relaxation constants which is in very good agreement with experiments. These results will be very important for photonic crystal-based nonlinear devices intended to deal with practical high repetition rate optical signals.