Silica Titania 1-D Photonic Crystals fabricated by rf-sputtering

Photonic band gap structures (PBGs), also known as photonic crystals (PC), evolved from an original idea of Yablonovitch1 who was inspired by semiconductor materials where electrons cannot have certain energy values due to the existence of a periodic electrostatic potential. PBGs materials are optical analogues of semiconductors, in the sense that the propagation of photons within a particular energy range is forbidden. These structures have a periodic refractive index variation (or dielectric constant), on a length scale of the order of optical wavelengths2. This periodicity prevents light from propagating through the material due to Bragg reflection, in a wavelength range of the order of the spatial period of the PBGs.