Electrochemical Modulation of Photonic Metamaterials

Contact: Jörg Weißmüller

Nanomaterials with tunable electronic structure exploit the large specific surface area of metal nanostructures along with the strategy of tuning the surface properties through the controlled introduction of space-charge regions for creating materials with tunable macroscopic properties. Photonic metamaterials provide an unconventional optical response in the extreme, negative refractive indices – by lithographically structured elements such as arrays of split-ring resonators (SRR). It is tempting to combine these two materials design strategies into a photonic metamaterial in which the space-charge at the surface of each SRR is controlled via an applied potential. Since the space charge couples into the electric resistivity, the resonance frequency of the metamaterials as well as the damping would be reversibly hifted. Our research indeed confirms that concept, exemplifying the new opportunities for designing functional nanomaterials which exploit nanoscale structure along with interfacial processes at electrode surfaces.

This work is performed in close cooperation with the Institut für Angewandte Physik at Karlsruhe Institute of Technology (KIT). Funding by the Center for Functional Nanostructures at KIT is acknowledged.


Selected Publications:


J. Weissmüller, R. N. Viswanath, D. Kramer, R. Würschum and H. Gleiter
Charge-Induced Reversible Strain in a Metal
Science 300 (2003) 312

S. Linden, C. Enkirch, M. Wegener, J. Zhou, T. Koschny and C. M. Soukoulis
Magnetic response in metamaterials at 100 THz
Science 306 (2004) 1351

L.-H. Shao, M. Ruther, S. Linden, S. Essig, K. Busch, J. Weissmüller and M. Wegener
Electrochemical Training and Modulation of Gold Nanostructure Optical Resonances
Adv. Mater. 22 (2010) 5173

M. Ruther, L.-H. Shao, S. Linden, J. Weissmüller, M. Wegener
Electrochemical Restructuring of Plasmonic Metamaterials
Appl. Phys. Lett. 98 (2011) 013112

The electron microscopy image depicts an array of lithographically structured gold split-ring resonators that act as a photonic metamaterial. Graphs show cyclic voltammograms that document the electrochemical signature of the metamaterial when undergoing cyclic changes of the electrode potential in aqueous NaF solution.
The electron microscopy image depicts an array of lithographically structured gold split-ring resonators that act as a photonic metamaterial. Graphs show cyclic voltammograms that document the electrochemical signature of the meta- material when undergoing cyclic changes of the electrode potential in aqueous NaF solution.

Color-coded map of extinction versus frequency (horizontal) and time (vertical) of a photonic metamaterial immersed in 0.7M NaF aqueous electrolyte during potential cycles. Variation of electrode potential is shown on the left. Drastic and reversible changes in resonance frequency and damping are apparent.
Color-coded map of extinction versus frequency (horizontal) and time (vertical) of a photonic metamaterial immersed in 0.7M NaF aqueous electrolyte during potential cycles. Variation of electrode potential is shown on the left. Drastic and reversible changes in resonance fre- quency and damping are apparent.