Realization of Fractal-Inspired Thermoresponsive Quasi-3D Plasmonic Metasurfaces with EOT-Like Transmission for Volumetric and Multispectral Detection in the Mid-IR Region

Abstract

We use a paradigmatic mathematic model known as Sierpiński fractal to reverse-engineer artificial nanostructures that can potentially serve as plasmonic metasurfaces as well as nanogap electrodes. Herein, we particularly demonstrate the possibility of obtaining multispectral extraordinary optical transmission-like transmission peaks from fractal-inspired geometries, which can preserve distinct spatial characteristics. To achieve enhanced volumetric interaction and thermal responsiveness within the framework, we consider a bilayer, quasi-three-dimensional (3D) configuration that relies on the unique approach of combining complementary and noncomplementary surfaces, while avoiding the need for multilayer alignment on the nanoscale. We implement an improved version of the model to (1) increase the volume of quasi-3D nanochannels and enhance the lightening-rod effect of the metasurfaces, (2) harness cross-coupling as a mechanism for achieving better sensitivity, and (3) exploit optical magnetism for pushing the resonances to longer wavelengths on a miniaturized platform. We further demonstrate vertical coupling as an effective route for ultimate miniaturization of such quasi-3D nanostructures. We report a wavelength shift up to 1666 nm/refractive index unit and 2.5 nm/°C, implying the usefulness of the proposed devices for applications such as dielectrophoretic sensing and nanothermodynamic study of molecular reactions in the chemically active mid-IR spectrum.

Dendritic Plasmonics for Mid-Infrared Spectroscopy

“…57 In this representation, each map is first calculated at 44 discrete wavelengths over a spectral range of 1.4 -10 µm. For each polarization, this forms a 3 rd rank tensor of dimensions X(308), Y(308) and λ (44). For each (x,y) spatial location, the tensor is then analyzed along the λ direction, and the λ max is extracted and assigned to an (x,y) spatial positon.…”

Hybrid Metamaterial Absorber Platform for Sensing of CO2 Gas at Mid‐IR

“…In contrast with metamaterial emitter, metamaterial absorber enables the conversion of light into heat for read out by the integrated system. With the aid of metamaterials absorber, the gas sensing system can achieve high wavelength selectivity, polarization dependence, and controlled light‐matter interaction . However, due to the small size of CO 2 molecule (232 pm), the near field coupling between the metamaterial absorber and gas is still limited.…”

Progress of infrared guided-wave nanophotonic sensors and devices

“…9a) [173,174]. Similar nanoplasmonic-enhanced MIR absorption sensing applications have also been demonstrated using bow-tie [175][176][177][178] and crooked [179] nanoplasmonic structures. In order to increase the sensing area, a high aspect ratio plasmonic nanotrench structure was proposed.…”