Multiple Defect Modes in Diamond Photonic Crystal

Abstract

Defect frequencies, degeneracy and mode field patterns of defect modes in diamond based photonic crystal (PC) are analyzed. An efficient method to create multiple defect frequency levels in the photonic band gap by degeneracy lifting is proposed. The degenerate dipole mode is split into two defect frequency levels by upsetting the symmetry about the origin. The diamond PC with our proposed defect structure has four defect frequency levels with two dipole and two quadrupole mode field patterns. It is shown that non-degenerate monopole and hexapole modes can be obtained by pulling up the acceptor levels from the dielectric band in diamond photonic crystals. Our proposed structure has a monopole and a hexapole mode that are very close in frequency. However, C6v symmetry of the triangular lattice guarantees their non-degeneracy.