We investigate the impact of light-forbidden exciton transitions in plasmon-emitter interactions beyond the weak coupling regime. We consider a V-type quantum emitter, with dipolar and quadrupolar excited states, placed at the subnanometric gap of a particle-on-a-mirror metallic cavity. We present a fully analytical description of the near-field population dynamics and far-field scattering spectrum of the hybrid system. Our approach enables us to reveal two realistic system configurations in which the dipole-inactive exciton alters significantly and in completely opposite ways the Purcell enhancement and Rabi splitting phenomenology, effectively enlarging or reducing the emitter lifetime and generating or removing spectral features in the cavity cross section.

中文翻译：

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弱耦合体系之外的等离子-发射极相互作用中的禁光跃迁。

我们研究了弱耦合体系以外的禁止激子跃迁在等离激元-发射极相互作用中的影响。我们考虑一个V型量子发射器，它具有偶极和四极激发态，被放置在镜上粒子金属腔的亚纳米间隙。我们对混合系统的近场种群动态和远场散射光谱进行了全面的分析描述。我们的方法使我们能够揭示两个现实的系统配置，其中偶极非激子显着改变，并且以完全相反的方式发生珀塞尔增强和拉比分裂现象，有效地增加或减少了发射器的寿命，并在腔体截面中产生或消除了光谱特征。