We investigated the optical properties of a circular photonic crystal (CPC) for which the distance between lattices was systematically distributed. The transmission spectra of CPC composed of alumina cylinders were examined in the frequency region from 0 to 20 GHz. We show that photonic gaps are obtained not only in CPCs but also in phase-shifted CPCs. The isotropic photonic gaps are evidenced by changes in the incident angle of a millimeter wave.
© 2004 Optical Society of America
N. Horiuchi, Y. Segawa, T. Nozokido, K. Mizuno, and H. Miyazaki, "Isotropic photonic gaps in a circular photonic crystal," Opt. Lett. 29, 1084-1086 (2004)