Tunable two-dimensional photonic crystal cavity all-optical switching infiltrated with liquid-crystal

Abstract

A novel photonic crystal (PC) all-optical switch based on the shift of defect mode is demonstrated. Two photonic crystal waveguides are connected by a photonic crystal cavity. The point defect of the photonic crystal cavity is filled with phenylacetylene liquid cyrstals intermingled with azobenzene. The output of the optical switch is controlled by adjusting the rotation angle of the liquid crystals' orientation vector. And the optical switch is numerically investigated by using the finite difference time domain (FDTD) method and plane wave expansion method. Numerical simulation shows that the optical switch based on the PC cavity can be changed by adjusting the applied linearly polarized light. Results show that the switch has low threshold power density, great extinction ratio, and small size.

High-efficiency ultra-fast all-optical photonic crystal diode based on the lateral-coupled nonlinear elliptical defect

“…When the periodic structure of the PhC is disrupted, a defect mode is stimulated within the photonic band gap, causing photons at, particular frequencies, to be localized within the defect region, while photons with frequencies deviating from the defect mode will be strongly scattered. Based on the photon localization property of PhCs, various optical devices have been developed, such as switches, [8][9][10][11][12] beam splitters, [13][14][15] diodes [16][17][18][19][20][21][22][23][24][25][26][27][28] and logic gates. [29][30][31][32] All-optical diodes (AODs) allow the light beam to propagate along one direction, while the opposite directional transmission is blocked.…”