Thermoplasmonic Controlled Optical Absorber Based on a Liquid Crystal Metasurface

Abstract

Metasurfaces can be realized by organizing subwavelength elements (e.g., plasmonic nanoparticles) on a reflective surface covered with a dielectric layer. Such an array of resonators, acting collectively, can completely absorb the resulting resonant wavelength. Unfortunately, despite the excellent optical properties of metasurfaces, they lack the tunability to perform as adaptive optical components. To boost the utilization of metasurfaces and realize a new generation of dynamically controlled optical components, we report our recent finding based on the powerful combination of an innovative metasurfaceoptical absorber and nematic liquid crystals (NLCs). The metasurface consists of self-assembled silver nanocubes (AgNCs) immobilized on a 50 nm thick gold layer by using a polyelectrolyte multilayer as a dielectric spacer. The resulting optical absorbers show a well-defined reflection band centered in the near-infrared of the electromagnetic spectrum (750−770 nm), a very high absorption efficiency (∼60%) at the resonant wavelength, and an elevated photothermal efficiency estimated from the time constant value (34 s). Such a metasurface-based optical absorber, combined with an NLC layer, planarly aligned via a photoaligned top cover glass substrate, shows homogeneous NLC alignment and an absorption band photothermally tunable over approximately 46 nm. Detailed thermographic studies and spectroscopic investigations highlight the extraordinary capability of the active metasurface to be used as a light-controllable optical absorber.

Phase Singularity in Random Gold Metasurface for Refractive Index Sensing: Experimental Demonstration and Theoretical Analysis

“…demonstrated the use of colloidal synthesis to create large-area metasurfaces, paving the way for scalable and cost-effective fabrication methods. Additionally, Khoruzhenko et al detailed the preparation of colloidal metasurfaces with tunable optical properties, while Petronella et al . demonstrated the dynamic tuning capabilities of liquid crystal-integrated metasurfaces.…”

Synergistic Antibacterial Properties of Silver Nanoparticles and Its Reducing Agent from Cinnamon Bark Extract

“…In the field of material science, silver nanoparticles are recognized for their versatility in applications in biomolecule sensing, diagnostic in healthcare systems, optics, and electronics applications. A particular example of the use of AgNPs in optics is the development of metasurfaces formed of self-assembled silver nanocubes (AgNCs) immobilized on a thick layer of gold, generating a new generation of dynamically controlled optical components [52].…”