Excitability of excitons and biexcitons in a ring cavity

Fast thermo-optical excitability in a two-dimensional photonic crystal

We experimentally demonstrate excitability in a semiconductor two-dimensional photonic crystal. Excitability is a nonlinear dynamical mechanism underlying pulselike responses to small perturbations in systems possessing one stable state. We show that a band-edge photonic crystal resonator exhibits class II excitability, resulting from the nonlinear coupling between the high-Q optical mode, the charge-carrier density, and the fast (sub-micros) thermal dynamics. In this context, the critical slowing down of the electro-optical dynamics close to the excitable threshold can delay the optical response by an amount comparable to the duration of the output pulse (5 ns). The latter results from a short thermal dynamical excursion along a high local intensity manifold of the phase space.

Analysis of the dynamics of a blue-violet Inx Ga1-x N laser with a saturable absorber

We report the results of numerical investigations of the dynamical behavior of a blue-violet InGaN laser with a specially incorporated saturable absorber. We have identified the nature of the bifurcation that occurs in the device dynamics and also the conditions that are necessary for self-pulsating and excitable operations. We also demonstrate the influence of the relevant device parameters on the laser dynamics and show how the properties of the saturable absorber and its position in the device have a considerable influence on the laser behavior. Finally theoretical investigations of the excitable behavior and a confirmation of the excitability properties of an InGaN laser are presented and discussed.