A paper titled “Ultralow Dispersion Multicomponent Thin-Film Chalcogenide Glass for Broadband Gradient-Index Optics” by Myungkoo Kang, Andrew M. Swisher, Alexej V. Pogrebnyakov, Liu Liu, Andrew Kirk, Stephen Aiken, Laura Sisken, Charmayne Lonergan, Justin CookTeodor MalendevychFedor KompanIvan DivlianskyLeonid B. GlebovMartin C. RichardsonClara Rivero-Baleine, Carlo G. Pantano, Theresa S. Mayer, and Kathleen Richardson has been published in Advanced Materials.

This paper benefited from a collegial set of CREOL collaborators that helped quantify the optical functionality of components possible from these materials.

Abstract: A novel photothermal process to spatially modulate the concentration of subwavelength, high-index nanocrystals in a multicomponent Ge-As-Pb-Se chalcogenide glass thin film resulting in an optically functional infrared grating is demonstrated. The process results in the formation of an optical nanocomposite possessing ultralow dispersion over unprecedented bandwidth. The spatially tailored index and dispersion modification enables creation of arbitrary refractive index gradients. Sub-bandgap laser exposure generates a Pb-rich amorphous phase transforming on heat treatment to high-index crystal phases. Spatially varying nanocrystal density is controlled by laser dose and is correlated to index change, yielding local index modification to +0.1 in the mid-infrared.