Non-Hermitian strong coupling of pure multipolar resonances and excitons in core-shell heterostructures
Phys. Rev. B 114, 125307 – Published 12 August, 2026
DOI: https://doi.org/10.1103/2znb-6l74
Abstract
Strong light-matter interaction in localized nanocavities is pivotal for quantum optics, yet conventional multipolar coupling is frequently obscured by parasitic background scattering. Here, we investigate the non-Hermitian strong coupling of pure multipolar resonances with two-dimensional excitons using core-shell heterostructures. Initially, by exciting an electric anapole state in a nanoparticle to neutralize electric dipole scattering, we isolate a nearly background-free magnetic dipole resonance to establish an electric-dipole-background-suppressed coupling platform. Advancing to higher-order modes, we employ a parity-matched excitation in an heterostructure to overcome the excitation bottleneck. This yields an ultrapure magnetic quadrupole state with a multipolar fraction exceeding 95% and massive Rabi splitting deep within the non-Hermitian strong-coupling regime. Furthermore, a quantum Heisenberg-Langevin formalism reveals the ultrafast temporal population dynamics, demonstrating a symmetric steady state and a 50-fs coherent energy exchange violently truncated by exotic non-Hermitian cooperative damping. Our work establishes multipolar radiation decoupling as a robust paradigm for high-order polaritonic devices.
