Carsten Ronning: Ion beam designed optical metasurfaces
Ion beam designed optical metasurfaces
Prof. Ronning will be opponent for Lert Chayanun’s dissertation the following day at 0900.
Merging industrial relevant ion beam technologies and the emerging science of ultra-thin active metasurfaces holds tremendous potential for the creation of large-scale, dynamically controlled optical meta-devices, and is a decisive step towards inherently planar optics. Novel metasurfaces for a broad and tunable spectral range can be designed by selective engineering of the refractive indices of thin dielectric films making use of ion beam irradiation through subwavelength-patterned masks or direct writing by a focused ion beam. The relevant dielectric material systems, which are used to create the metasurfaces - phase change materials, phase transition materials, silicon - offer low optical losses and possible dynamic control of their optical properties by an external stimulus. In this seminar, I will show three examples based on ion irradiated VO2 , Ge2Sb2Te5  and silicon .
 Active optical metasurfaces based on defect-engineered phase-transition materials
J. Rensberg, S. Zhang, Y. Zhou, A.S. McLeod, C. Schwarz, M. Goldflam, M. Liu, J. Kerbusch, R. Nawrodt, S. Ramanathan, D. N. Basov, F. Capasso, C. Ronning, M. Kats
Nano Letters 16, 1050 (2016)
 Metasurfaces enabled by locally tailoring disorder in phase-change materials
M. Hafermann, P. Schöppe, J. Rensberg, C. Ronning
ACS Photonics 5, 5103 (2018)
 Flat optical and plasmonic devices using area-selective ion-beam doping of silicon
J. Salman, M. Hafermann, J. Rensberg, C. Wan, R. Wambold, B.S. Gundlach, C. Ronning, M.A. Kats
Advanced Optical Materials 6, 1701027 (2018)