Modal selective tuning in a photonic crystal cavity

We present a way to selectively tune the properties of the degenerated modes confined in a single point defect two-dimensional photonic crystal cavity based on a triangular lattice of air holes. We investigate the dependence of the modal properties of the resonator on the position of the first neighbor holes, showing that it is possible to finely tune the resonant frequency of only one of these two modes and to increase the quality factor of the mode that has no frequency shift. This is achieved by controlling the wavevector components inside the cavity. This approach is a viable strategy for the development and the optimization of several innovative devices based on bi-modal cavity arrays, such as arrays of integrated optical filters and optical read-out sections for biosensing applications.