Direct Imprint of Optical Functionalities on Free-Form Chalcogenide Glasses

Scalable surface patterning of chalcogenide glasses is the crux for many optical applications of these promising optical materials. Here, a novel, resist-free surface patterning of chalcogenide glasses with 3D relief microstructures is introduced, using direct radiation-assisted thermal imprint. The imprint is based on a nanocomposite mold made of a carbon nanotube matrix and polydimethylsiloxane resin. To allow nanoimprint, the mold and glass substrate are confined between two elastic membranes, pneumatically pressed against each other, and controllably radiated by an infrared bulb. Since chalcogenide glass is transparent to infrared radiation, the radiation is mostly absorbed in the mold due to the embedded carbon nanotubes, so that the glass–mold interface is heated to the imprint temperature. By using this approach, the first of its type direct imprint of chalcogenide glass of any arbitrary form is demonstrated, including flat substrates and convex aspheric lenses. The composition and structure of imprinted chalcogenide glass are analyzed, and it is demonstrated that they are well maintained throughout the imprint. It is optically characterized both in transmission and reflection modes. It is believed that the innovation provides a quantum leap in the micro- and nano-scale processing of chalcogenide glasses, and opens the pathway to their numerous applications.