The First voltage-controlled Switchable Window/Mirror Metadevice !!!

We reported on the First ever 'electrotuneable window/mirror' metamaterial device. Such a reversible electrotunable metadevice was realized based on voltage-controlled self-assembly/disassembly of 16 nm gold nanoparticles at the interface between two immiscible electrolyte solutions (oil and water). A dense 2D array of gold nanoparticles at the interface can reflect light like a 'mirror', whereas a sparse array can allow light to pass through, just like a 'window'.

We show that optical properties such as reflectivity and spectral position of the absorption band can be varied in situ within ±0.5 V. This observed effect is in excellent agreement with theoretical calculations corresponding to the change in average interparticle spacing. This electrochemical fully tunable nanoplasmonic platform can be switched from a highly reflective ‘mirror’ to a transmissive ‘window’ and back again. This study opens a route towards realization of tunable plasmonic metamaterials including switchable mirrors/windows, optical filters, displays, energy harvesting devices, and sensors in the future.