Abstract

2D Photonic Crystals (2DPC) allow strong light confinement due to high-Q resonances, which can be realized by point defects (nanocavity) in a periodic array of holes. In III-V semiconductor materials, electronic confinement can also be achieved through the inclusion of nanostructures (i.e. quantum wells). Both electronic and optical confinement leads to the enhancement of light-matter interaction, making 2DPC systems a good platform for non-linear studies. Additionally, new unexplored regions of electronic, thermal and photonic lifetimes are also attainable in 2DPC. We present here unpublished results on optical bistability (OB), self-sustained oscillations and excitability in 2DPC. OB is a key phenomenon in the road of all optical signals processing, in particular for optical memories. Two ingredients are needed in order to obtain OB: a resonance capable of localizing the light intensity in the spectral domain, and a non-linear effect that changes the spectral response as a function of the injected intensity. Under certain conditions for the injection of a nearly resonant beam, two stable states for the transmission/reflection through the device can coexist. Few experimental works already demonstrated electronic OB in 2DPC[1,2]. Another interesting nonlinear dynamical behaviour that we address in the same 2DPC is the excitability. Well known in biological systems, an excitable system possesses only one stable state and reacts to an external perturbation in the form of all-or-nothing pulse responses, depending on whether the perturbation is above or below a certain threshold [3]. 2DPC nanocavity excitable response is demonstrated here for the first time and can be considered as a potential neuron-like ultrafast system.

© 2011 Optical Society of America