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Ultralow Dispersion Multicomponent Thin‐Film Chalcogenide Glass for Broadband Gradient‐Index Optics |
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| Authors: | Andrew M. Swisher Alexej V. Pogrebnyakov Liu Liu Andrew Kirk Stephen Aiken Laura Sisken Charmayne Lonergan Justin Cook Teodor Malendevych Fedor Kompan Ivan Divliansky Leonid B. Glebov Martin C. Richardson Clara Rivero‐Baleine Carlo G. Pantano Theresa S. Mayer Kathleen Richardson |
| Affiliation: | 1. Department of Electrical Engineering, Pennsylvania State University, PA, USA;2. Missiles and Fire Control, Lockheed Martin Corporation, Orlando, FL, USA;3. CREOL, College of Optics and Photonics, University of Central Florida, Orlando, FL, USA;4. Department of Materials Science and Engineering, Pennsylvania State University, PA, USA |
| Abstract: | A novel photothermal process to spatially modulate the concentration of sub‐wavelength, 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. |
| Keywords: | achromatic microlenses chalcogenide glass gradient refractive index optical nanocomposites photothermal process |