Towards Electrotuneable Nanoplasmonic Fabry–Perot Interferometer

Abstract

Directed voltage-controlled assembly and disassembly of plasmonic nanoparticles (NPs) at electrified solid–electrolyte interfaces (SEI) offer novel opportunities for the creation of tuneable optical devices. We apply this concept to propose a fast electrotuneable, NP-based Fabry–Perot (FP) interferometer, comprising two parallel transparent electrodes in aqueous electrolyte, which form the polarizable SEI for directed assembly–disassembly of negatively charged NPs. An FP cavity between two reflective NP-monolayers assembled at such interfaces can be formed or deconstructed under positive or negative polarization of the electrodes, respectively. The inter-NP spacing may be tuned via applied potential. Since the intensity, wavelength, and linewidth of the reflectivity peak depend on the NP packing density, the transmission spectrum of the system can thus be varied. A detailed theoretical model of the system’s optical response is presented, which shows excellent agreement with full-wave simulations. The tuning of the peak transmission wavelength and linewidth is investigated in detail. Design guidelines for such NP-based FP systems are established, where transmission characteristics can be electrotuned in-situ, without mechanically altering the cavity length.

An electro-tunable Fabry–Perot interferometer based on dual mirror-on-mirror nanoplasmonic metamaterials

“…This work presents an electro-tunable FPI cavity formed between dual mirror-on-mirror nanoplasmonic metamaterials. The proposed design ensures superior transmittance characteristics of an FPI (with narrow, intense, and widely tunable transmission peaks), not achieved in our previous work [31] -involving voltage-controlled self-assembly of gold NPs on transparent electrodes. Those transparent electrodes played no significant role in the cavity's optical properties.…”

Electrochemical metamaterials

“…This is, e.g. a theory of functioning of Fabry-Perot cell (cavity) that would 'trap' light between two semi-transparent electrode plates, and filter the transmission of light through the cell, by controlling the density of NP arrays on the plates through NP electrosorbtion/desorption from/to electrolyte solution filling the cavity [76,77]. It is an interesting alternative to the standard mechanical adjustment of the cavity length, as it shows opportunities of sharp light transmission filtering by tiny voltage variation.…”

Optical response of electro-tuneable 3D superstructures of plasmonic nanoparticles self-assembling on transparent columnar electrodes

“…We then present further extension to an N-layer system. Finally, the ZnO columns are introduced into the model by recalculating the dielectric function of the medium surrounding the NPs, using the Maxwell-Garnett formula [12], to obtain a comprehensive theoretical framework, which is verified against full-wave simulations.…”

“…An alliance of the two worlds possesses immense possibilities towards realizing in-situ electrically tuneable nanoplasmonic devices [12] on transparent electrodes, e.g. Fabry-Perot interferometers, optical filters, etc.…”

“…where ZnO columns are arranged in a triangular lattice in an aqueous (water) environment. The dielectric function of the water/ZnO composite surrounding medium can then be determined from the Maxwell-Garnet (MG) approximation [12,43], given by…”