It is well known that the absorption efficiency of a suspended monolayer graphene in the optical wavelength rang is only 2.3%, which limits its optoelectronic applications. In this work, we numerically demonstrate dual-band absorption enhancement of monolayer graphene at optical frequency, with the maximum absorption efficiency reaching to about 70% under optimum conditions. The dual-band absorption enhancement arises from the excitations of surface plasmon polaritons and magnetic dipole resonances in metamaterials. The monolayer graphene is sandwiched between a periodic array of Ag nanodisks and a SiO spacer supported on an Ag substrate. The resonance wavelengths of two absorption bands arising from surface plasmon polaritons and magnetic dipole resonances can be easily tuned by the array period and the diameter of the Ag nanodisks, respectively. Our designed graphene light absorber may find some potential applications in optoelectronic devices, such as photodetectors.
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http://dx.doi.org/10.1364/OE.25.012061 | DOI Listing |
J Am Chem Soc
December 2024
Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
The nonlinear optical response in graphene is finding increasing applications in nanophotonic devices. The activation and enhancement of second harmonic generation (SHG) in graphene, which is generally forbidden in monolayer and AB-stacked bilayer graphene due to their centrosymmetry, is of urgent need for nanophotonic applications. Here, we present a comprehensive study of SHG performance of twisted multilayer graphene structures based on stacking engineering.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Materials, Imperial College London, London, SW7 2AZ, UK.
Topological Insulators (TIs) are promising platforms for Quantum Technology due to their topologically protected surface states (TSS). Plasmonic excitations in TIs are especially interesting both as a method of characterisation for TI heterostructures, and as potential routes to couple optical and spin signals in low-loss devices. Since the electrical properties of the TI surface are critical, tuning TI surfaces is a vital step in developing TI structures that can be applied in real world plasmonic devices.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Institute of Chemical Engineering Sciences, Foundation of Research and Technology- Hellas (FORTH/ICE-HT), Stadiou Street, Platani, Patras 26504, Greece.
Due to their outstanding electrical and thermal properties, graphene and related materials have been proposed as ideal candidates for the development of lightweight systems for thermoelectric applications. Recently, the nanolaminate architecture that entails alternation of continuous graphene monolayers and ultrathin polymer films has been proposed as an efficient route for the development of composites with impressive physicochemical properties. In this work, we present a novel layer-by-layer approach for the fabrication of highly ordered, flexible, heat-resistant, and electrically conductive freestanding graphene/polymer nanolaminates through alternating Marangoni-driven self-assembly of reduced graphene oxide (rGO) and poly(ether imide) (PEI) films.
View Article and Find Full Text PDFACS Nano
December 2024
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Ultrafast thermal switches are pivotal for managing heat generated in advanced solid-state applications, including high-speed chiplets, thermo-optical modulators, and on-chip lasers. However, conventional phonon-based switches cannot meet the demand for picosecond-level response times, and existing near-field radiative thermal switches face challenges in efficiently modulating heat transfer across vacuum gaps. To overcome these limitations, we propose an ultrafast thermal switch design based on pump-driven transient polaritons in asymmetric terminals.
View Article and Find Full Text PDFACS Nano
December 2024
Center for Advanced Quantum Studies, School of Physics and Astronomy, Beijing Normal University, Beijing 100875, China.
Introducing quantum confinement has shown promise to enable control of charge carriers. Although recent advances make it possible to realize confinement from semiclassical regime to quantum regime, achieving control of electronic potentials in individual nanoscale quantum dots (QDs) has remained challenging. Here, we demonstrate the ability to tune quantum confined states in individual nanoscale graphene QDs, which are realized by inserting nanoscale monolayer WSe islands in graphene/WSe heterostructures via interfacial engineering.
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