Defects and Applications

Defects are not necessarily bad in Photonic Crystal (PC). Ironically, an interesting application can be made out of the defects. PC is known for its feature which traps light and does not allow light to propagate through it. By intentionally introduce defects to the material, light can propagate in between the photonic band gap but only in those regions defined by the defects structure.In other words, by introducing defects to the PC in a controlled manner, a light guiding property is added up to the material.


The advantage of 2D photonic crystals’ excellent wave guiding property has been used in many of their applications.As shown in the figures above, light is propagated in some kind of path. This occurrence happened after a line defect is introduced into the photonic structure. In the figures,defects made it possible to guide the wave into 90 degrees bend and split the beam to two directions, also known as beam splitters.