Ion beam tailoring of phase change materials for metasurfaces

• Applicant: Professor Dr. Carsten Ronning
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 389346299

Metasurfaces are artificially structured and optically thin films, which can be precisely engineered to control the amplitude, polarization, or phase of light beams. Metasurfaces enable flat optics and will revolutionize photonics, as conventional litho¬graphy and deposition methods can be used to fabricate devices from simple planar to complex optical systems. Within this project we will first study the ion-solid-interaction in phase change (GeSbTe) and phase transition (VO2 and SmNiO3) materials, as these materials undergo a large optical contrast upon phase transition from their respective metallic to insulating phase. To control the phase transition, we will systematically study the dependence of the ion beam parameters on the change of the optical properties in these materials. Secondly, metasurfaces for a broad and tun¬able spectral range will be designed by selective doping or defect engineering of these materials making use of ion beam irradiation either through sub¬wave¬length-patterned masks or by direct writing using a focused ion beam. Finally, as selective doping and defect engineering by ion irradiation enables inherently flat metasurfaces, three-dimensional hierarchical systems can be build layer by layer at the end of the project: a long-term vision in optics.

• DFG Programme: Research Grants
• International Connection: USA
• Cooperation Partners: Professor Dr. Mikhail Kats; Professor Dr. Shriram Ramanathan