Numerical analysis of plasmonic metasurfaces for fluorescence enhancement

Abstract

The paper presents an extensive numerical analysis performed by three-dimensional (3D) simulations using the finite difference in time and space (FDTD) method to identify the optimal geometry, size and configuration of the nano-antennas that constitute a plasmonic metasurface. The aim was to achieve the highest resonance at various wavelengths (NIR-VIS), for local enhancement of the excitation field and collection efficiency of emitted photons. We investigated ten different types of metals, two shapes (disks and U-shape resonators) and various geometrical parameters for the nanoresonators composing the metasurface. The best results for Rhodamine 6G excitation and emission were obtained using silver resonators with 105 nm diameter of the cylinder elements in a rectangular array with a 110 nm period, and with 110 nm long U-shape placed at a period of 40 nm.