Two dimensional photonic band gap pattering in thin chalcogenide glassy films

Photonic band gap (PBG) based elements can significantly contribute to future integrated optical circuits. However, at the wavelength of 1500 nm, they require about 100 nm feature size lithographic processes, which, until now, have been typically accomplished with the help of e-beam lithography. Taking into account that all non-periodic features, e.g. waveguides and cavities, require only ∼300 nm resolution, the process can be separated in two stages. First, interference lithography is used for creation of periodic patterns with minute feature sizes. Second, the non-periodic lower resolution features are added by standard ultraviolet lithography. Using this method 1.3 μm thickness waveguides in 100 nm feature size hexagonal PBG environment were fabricated from high refractive index ( n = 2.2–2.5) chalcogenide photoresists.