Strong Optical Coupling of Lattice Resonances in a Top-down Fabricated Hybrid Metal–Dielectric Al/Si/Ge Metasurface

Abstract

Optical metasurfaces enable the manipulation of the light–matter interaction in ultrathin layers. Compared with their metal or dielectric counterparts, hybrid metasurfaces resulting from the combination of dielectric and metallic nanostructures can offer increased possibilities for interactions between modes present in the system. Here, we investigate the interaction between lattice resonances in a hybrid metal–dielectric metasurface obtained from a single-step nanofabrication process. Finite-difference time domain simulations show the avoided crossing of the modes appearing in the wavelength-dependent absorptance inside the Ge upon variations in a selected geometry parameter as evidence for strong optical coupling. We find good agreement between the measured and simulated absorptance and reflectance spectra. Our metasurface design can be easily incorporated into a top-down optoelectronic device fabrication process with possible applications ranging from on-chip spectroscopy to sensing.

Tunable Surface Plasmon-Polaritons Interaction in All-Metal Pyramidal Metasurfaces: Unveiling Principles and Significance for Biosensing Applications

“…On the other hand, the flourishing field of optical metasurfaces is attracting growing interest due to its remarkable ability to precisely manipulate and adapt optical properties. − These metasurfaces harness the near-field overlap between neighboring nanoparticles, mimicking the electronic bands found in well-localized atomic orbitals. Within the domain of plasmonic nanoresonators, this phenomenon–often termed as plasmon hybridization– enables tailored adjustments to optical behavior, thus facilitating the creation of distinctive optical features through meticulous design of the elementary plasmonic constituents. − Indeed, groundbreaking achievements have been demonstrated in spatial resolution levels, particularly in light’s polarization control, holograms, and wavefront manipulation. Additionally, unprecedented efficiencies have been achieved in bending and focusing light .…”