Abstract

Two-dimensional (2D) photonic crystals have attracted increasing attention for their easy fabrication (in comparison with the 3D crystals) with the current technology of semiconductor process [1,2] and the significant application of suppressing spontaneous emission in optical devices, especially in semiconductor lasers. Towards the application to optical devices, investigation of defect modes which provide an isolated energy level inside the band gap has become highly required. Studies of defect modes in a 3D photonic crystal showed that an “acceptor” defect creates a single level and “donor” defect creates multiple levels inside the band gap [3,4], On the other hand, investigation of defect modes in 2D crystals so far was mainly carried out for the acceptor mode [4-7], especially for the E- polarised waves in a square lattice of dielectric-rods- in-air structure which shows a tendency to form double acceptor levels [4-6], In htis paper, we theoretically demonstrate that the 2D triangular dielec- tric-rods-in-air structure can achieve both a single acceptor level and a single sharp donor level at the middle of a large band gap by using a supercell lattice.

© 1996 Optical Society of America