Dual Control of Enhanced Quasi-Bound States in the Continuum Emission from Resonant c-Si Metasurfaces

Zhenghe Zhang; Chaojie Xu; Chen Liu; Man Lang; Yuehao Zhang; Minghao Li; Wanli Lu; Zefeng Chen; Chinhua Wang; Shaojun Wang; Xiaofeng Li

doi:10.1021/acs.nanolett.3c02148

Dual Control of Enhanced Quasi-Bound States in the Continuum Emission from Resonant c-Si Metasurfaces

Nano Lett. 2023 Aug 23;23(16):7584-7592. doi: 10.1021/acs.nanolett.3c02148. Epub 2023 Aug 4.

Authors

Zhenghe Zhang^{1

2}, Chaojie Xu³, Chen Liu^{1

2}, Man Lang^{1

2}, Yuehao Zhang^{1

2}, Minghao Li⁴, Wanli Lu⁵, Zefeng Chen^{1

2}, Chinhua Wang^{1

2}, Shaojun Wang^{1

2}, Xiaofeng Li^{1

2}

Affiliations

¹ School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China.
² Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006, China.
³ Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials Devices, Soochow University, Suzhou 215123, China.
⁴ Department of Physics and Swiss Nanoscience Institute, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
⁵ School of Materials Science and Physics, China University of Mining and Technology, Xuzhou 221116, China.

PMID: 37539848
DOI: 10.1021/acs.nanolett.3c02148

Abstract

Optical bound states in the continuum (BICs) offer strong interactions with quantum emitters and have been extensively studied for manipulating spontaneous emission, lasing, and polariton Bose-Einstein condensation. However, the out-coupling efficiency of quasi-BIC emission, crucial for practical light-emitting devices, has received less attention. Here, we report an adaptable approach for enhancing quasi-BIC emission from a resonant monocrystalline silicon (c-Si) metasurface through lattice and multipolar engineering. We identify dual-BICs originating from electric quadrupoles (EQ) and out-of-plane magnetic dipoles, with EQ quasi-BICs exhibiting concentrated near-fields near the c-Si nanodisks. The enhanced fractional radiative local density of states of EQ quasi-BICs overlaps spatially with the emitters, promoting efficient out-coupling. Furthermore, coupling the EQ quasi-BICs with Rayleigh anomalies enhances directional emission intensity, and we observe inherent opposite topological charges in the multipolarly controlled dual-BICs. These findings provide valuable insights for developing efficient nanophotonic devices based on quasi-BICs.

Keywords: collective resonances; dielectric nanoantenna array; multipolar control; optical bound states in the continuum; polarization-vortex emission; radiation efficiency.