Sub-micron sculpturing on chalcogenide films

Arsenic based chalcogenide glasses present several advantages for nano-structured optical devices in the infrared. First they possess a good transparency in this optical window, second their amorphous nature is ideal for coating based applications or for hybrid integration, third their photo-structural transformation properties give the possibility of creating high-resolution patterns on films and finally their high index make them particularly suitable for the fabrication of photonic crystal devices. We have demonstrated the fabrication of two-dimensional and three-dimensional (wood-pile) photonic crystal structures for typically 500 nm period structures using interferometric lithography to create the periodic pattern. We show here different techniques in order to obtain specific patterns on the chalcogenide glass using a combination of illumination, etching and redeposition techniques. Moreover, in order to create very steep contrast, we have used the fact that silver ions can freely propagate in the glass under light action, providing a very effective contrast between illuminated and non-illuminated regions. 130 nm patterns with a 500 nm periodicity have been obtained using silver doping of chalcogenide glasses. We will finally show different examples of pattern sculpturing using different illumination and film preparation conditions.