ABSTRACT
Interest in photonic crystals (PCs) has recently been increasing from both scienti c and technological viewpoints of the photonics research, since the seminal reports independently published by Yablonovitch1 and John2 two decades ago. This is because the PC structures have the prospects of manipulating the ow of light at will.3 The PCs are dielectric materials possessing spatial structures with a periodic scale comparable to that of electromagnetic waves, resulting in the appearance of forbidden regions for photons in the dispersion spectrum. These regions are known as photonic band gaps (PBGs). Novel PC systems could cause some intriguing optical phenomena such as the strong localization of photons, the sharp bending of light propagation, and the suppression or enhancement of light emission from small-size devices.
