Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 76: Plasmonics & Nanooptics V: Nanostructures and Nanoantennae

O 76.3: Vortrag

Donnerstag, 4. April 2019, 11:00–11:15, H8

A freestanding 40 nm thick metasurface lens — •Till Leuteritz, Mike Prämassing, and Stefan Linden — Physikalisches Institut, Universität Bonn, D-53115

Miniaturization of electronics has lead to a rapid rise of new technologies like cellphones and tablets. The limiting factor of a cellphones thickness today is the lens. A solution to reduce the thickness of lenses was presented by A. Francesco et al in 2012 [1]. They demonstrated a metasurface consisting of V-shaped antennas which introduces the phase profile required for lensing. Even though most metasurfaces are a few ten nanometers thick they are typically fabricated on a 100 um thick inflexible glass substrate. In our work we present a solution to overcome this problem.

Considering Babinets principle, we use an inverted design of V-shaped plasmonic slot antennas in a freestanding 40nm gold film. They are produced by milling the V-shaped structures into carbon film with a focused ion beam. Thermal evaporation of the gold film followed by a plasma etching step to remove the carbon yields the desired structure.

We find an agreement between modes of an individual V-shaped antenna determined by energy electron loss spectroscopy and simulations done with a finite elemente solver. In addition we experimentally show the focusing of our metasurface lens and the simulations to optimize it.

[1] Aieta, Francesco, et al., Nano letters 12.9 (2012): 4932-4936.