High refractive index chalcogenide glass for photonic crystal applications

A high refractive index Te-enriched bulk chalcogenide glass Ge20As20Se14Te46 (n approximate to 3.3) has been patterned by ablation using four-and two-beam interference femto-second laser setups operating at 800 nm. The regular arrays of 0.8 mu m diameter and more than 0.8 mu m depth holes and/or grooves of typical size of 1 x 1 mm(2) have been written on the surface of the glass in a time-scale of 1 second with 50 femtosecond pulses. The high photosensitivity of this narrow-gap semiconductor glass to the femtosecond irradiation is ascribed to a free electron absorption typical of metals, which is caused by laser-induced heating of the glass. (c) 2007 Optical Society of America.