title: Evanescent-Vacuum-Enhanced Photon-Exciton Coupling and Fluorescence Collection.
abstract: An evanescent optical mode existing in various nanophotonic structures always acts as a cavity mode rather than an electromagnetic vacuum in the study of cavity quantum electrodynamics (CQED). Here we show that taking the evanescent mode as an electromagnetic vacuum in which the nanocavity is located is possible through the optical mode design. The proposed evanescent vacuum enables us to enhance both the reversible photon-exciton interaction and fluorescence collection. By embedding the custom-designed plasmon nanocavity into the evanescent vacuum provided by a metallic or dielectric nanowire, the photon-exciton coupling coefficient can achieve 4.2 times that in vacuum due to the exponential decay of the evanescent wave, and spontaneously emitted photons with Rabi splitting can be guided by an evanescent wave with a collection efficiency of 47% at most. Electromagnetic vacuum engineering at subwavelength scale holds promise for controlling the light-matter interaction in quantum optics, CQED, and on-chip quantum information.
authors.affiliation: State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Department of Physics, Peking University, Beijing 100871, China.
authors.forename: Juanjuan
authors.initials: J
authors.lastname: Ren
authors.affiliation: State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Department of Physics, Peking University, Beijing 100871, China.|Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Gu
authors.affiliation: State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Department of Physics, Peking University, Beijing 100871, China.
authors.forename: Dongxing
authors.initials: D
authors.lastname: Zhao
authors.affiliation: State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Department of Physics, Peking University, Beijing 100871, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China.|State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China.
authors.forename: Tiancai
authors.initials: T
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Mesoscopic Physics, Collaborative Innovation Center of Quantum Matter, Department of Physics, Peking University, Beijing 100871, China.|Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China.
authors.forename: Qihuang
authors.initials: Q
authors.lastname: Gong