Parallel lithographic fabrication of micro-optical lenslets by photoexpansion in chalcogenide glasses

Chalcogenide glasses may be used to form refractive and relief structures for applications in integrated optics or optical data storage. Photodarkening and the attendant photo-expansion effect are the primary recording mechanisms in these materials. Photodarkening only a small region of the glass leads to stress at the interface between the darkened and unexposed regions due to volume differences between these two regions. This enhances the volume changes of the photoexpansion effect to fabricate surface relief gratings. This work focuses on using the large volume changes and the non-local nature of the photo-expansion effect to fabricate micro-lenses on the surface of As/sub 2/S/sub 3/ glasses. Previously reported lenslets were fabricated by irradiating samples with focused He-Ne laser light at 632.8 nm.