Bistability phenomena based on frequency-sensitive self-collimation in nonlinear photonic crystals

By introducing the change of beam behavior near the frequency sensitive self-collimation point, a new kind of bistability is observed in a finite nonlinear photonic crystal (PhC). The mechanism of such a PhC bistability is from the complex interplay between cavity resonance, nonlinearity and beam behavior. Additionally, it has unique properties, including: high frequency sensitivity, small volume, short switching time, robustness and position flexibility. With the consideration of beam behavior, a new theory based on the coupled-mode equation has been constructed, whose result agrees with the numerical one very well. The new PhC bistability could be widely used to design various optical devices, as a bistable all-optical switch has also been demonstrated.