The photonic band gap material may be characterized by periodicity of dielectric properties in two or three dimensions, and may comprise {HEAD ~ holes}, {TAIL ~ defects}, cavities, or other elements in layers of dielectric materials that give rise to the band gap behavior 
The photonic band gap material may be characterized by periodicity of dielectric properties in two or three dimensions , and may comprise { HEAD ~ holes } , { TAIL ~ defects } , cavities , or other elements in layers of dielectric materials that give rise to the band gap behavior
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH