Light–matter interactions in the coupling system of quantum emitter and hyperbolic nanorod

Abstract

Plasmonic nanostructures are widely applied to couple with quantum emitters (QEs), so as to improve the optical performances of QE and obtain advanced photonic devices, such as the quantum photon source, quantum circuit. However, the huge loss of plasmonic nanostructures greatly hinders the future development of plasmon–QE hybrid systems. Herein, we propose the hyperbolic nanorods (HNR) which are built by alternate Au and SiO2 thin layers. The size of HNR discussed in this paper is mainly around 40 × 50 × 60 nm3, which is a subwavelength size benefiting for device miniaturization and integration. The photonic resonant mode of HNR can be tuned by simply changing its length/width ratio. Due to the hybridization of the surface plasmon polariton resonances associated with each metal–dielectric interface, the HNR possesses the advantage of small mode volume (V) as the Au plasmonic nanorod (PNR) with similar size, and its mode quality factor (Q) can be larger due to the lower loss. Therefore, when coupled with a resonant QE, the Purcell factor in HNR/QE is ∼20 times larger than that in the PNR/QE system. Furthermore, the HNR/QE hybrid also demonstrates obvious superiority over the PNR/QE in generating strong coupling and quantum entanglement. With the features of small V and low loss, it is believed that the HNR can not only greatly improve the optical properties of QE, but also be a powerful nanostructure for studying light–matter interactions.