Plasmonic quantum effects on single-emitter strong coupling

Nanophotonics

article

Cristian Ciracì¹  Radoslaw Jurga¹  Muhammad Khalid¹  Fabio Della Sala¹ 

[1] Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia;Dipartimento di Matematica e Fisica “E. De Giorgi”, Università del Salento;Institute for Microelectronics and Microsystems (IMM-CNR), Campus Unisalento

关键词: plasmonics;    strong coupling;    nonlocal response;    hydrodynamic model;    fluorescence;   

DOI  :  10.1515/nanoph-2019-0199

学科分类：社会科学、人文和艺术（综合）

来源: De Gruyter

【 摘 要 】

Coupling between electromagnetic cavity fields and fluorescent molecules or quantum emitters can be strongly enhanced by reducing the cavity mode volume. Plasmonic structures allow light confinement down to volumes that are only a few cubic nanometers. At such length scales, nonlocal and quantum tunneling effects are expected to influence the emitter interaction with the surface plasmon modes, which unavoidably requires going beyond classical models to accurately describe the electron response at the metal surface. In this context, the quantum hydrodynamic theory (QHT) has emerged as an efficient tool to probe nonlocal and quantum effects in metallic nanostructures. Here, we apply state-of-the-art QHT to investigate the quantum effects on strong coupling of a dipole emitter placed at nanometer distances from metallic particles. A comparison with conventional local response approximation (LRA) and Thomas-Fermi hydrodynamic theory results shows the importance of quantum effects on the plasmon-emitter coupling. The QHT predicts qualitative deviation from LRA in the weak coupling regime that leads to quantitative differences in the strong coupling regime. In nano-gap systems, the inclusion of quantum broadening leads to the existence of an optimal gap size for Rabi splitting that minimizes the requirements on the emitter oscillator strength.

【 授权许可】

CC BY