Single point defect photonic crystal nanocavity with ultrahigh quality factor achieved by using hexapole mode

Photonic crystal (PhC) nanocavities with an extremely high quality factor (Q) based on a point defect are fabricated and their properties are studied. Their confinement of light is based on rotational symmetry, which forms a hexapole mode with a Q of 3.2x10(5). It demonstrates that this nanocavity is an alternative candidate for achieving an ultrahigh Q. In addition, we observed bistable behavior based on the thermo-optic effect at a threshold power of a few 100 mu W. We also investigated the dynamic properties of this cavity, where we observed that the cavity exhibits a smaller Q at a higher input power. (C) 2007 American Institute of Physics.