Graphene Absorption Enhanced by Quasi-Bound-State-in-Continuum in Long-Wavelength Plasmonic–Photonic System

Abstract
Graphene plasmonic structures can support enhanced and localized light–mater interactions within extremely small mode volumes. However, the external quantum efficiency of the resulting devices is fundamentally limited by material scattering and radiation loss. Here, such radiation loss channels are suppressed by tailoring the structure to support a symmetry-protected bound-state-in-the-continuum (BIC) system. With practical loss rates and doping level in graphene, over 90% absorption near critical coupling is expected from numerical simulation. Experimentally measured peak absorption of 68% is achieved in such a tailored graphene photonic–plasmonic system, with maximum 50% contrast to the control sample without graphene. Significant reduction of the plasmon absorption for a different spacer thickness verifies the sensitivity of the system to the quasi-BIC condition.
Description
This is the peer reviewed version of the following article: Kananen, T., Wiggins, M., Wang, Z., Wang, F., Soman, A., Booksh, K., Alù, A., Gu, T., Graphene Absorption Enhanced by Quasi-Bound-State-in-Continuum in Long-Wavelength Plasmonic–Photonic System. Adv. Optical Mater. 2022, 2201193. https://doi.org/10.1002/adom.202201193, which has been published in final form at https://doi.org/10.1002/adom.202201193. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited. This article will be embargoed until 09/07/2023.
Keywords
bound-states-in-the-continuum, critical coupling, graphene, mid-infrared, plasmon
Citation
Kananen, T., Wiggins, M., Wang, Z., Wang, F., Soman, A., Booksh, K., Alù, A., Gu, T., Graphene Absorption Enhanced by Quasi-Bound-State-in-Continuum in Long-Wavelength Plasmonic–Photonic System. Adv. Optical Mater. 2022, 2201193. https://doi.org/10.1002/adom.202201193