It's the property of the material which allow only certain bandwidth of wavelength. Materials that exhibit this property is known as photonic crystal. In order to exhibit this property the material has to have a periodic arrangement of dielectric structures with periodicity of the order of wavelength.

See: www.physorg.com/pdf84452630.pdf

J. D. Joannopoulos has written:

'Photonic crystals' -- subject(s): Photons, Crystal optics

'The Physics of Hydrogenated Amorphous Silicon'

we already hit the galactic photonic belt said god the father.

Checkov radiation