Bimetal-wrapped nanowire structure for improved efficiency and unidirectional emission of single-photon sources

To meet the increasing demand for wavelength scaled light-emitting devices, this study developed a novel dielectric nanowire configuration comprising two distinct metals. This structure is expected to function as a unidirectional light source owing to the reflection occurring at the junctions of the two metals. The performance of this structure as a unidirectional nanosized light source was validated using finite-difference time-domain (FDTD) simulations. With a minimal waveguide width of w = 115 nm, this structure mitigates the risks associated with free-space radiation and interference from other wavelength modes. The subwavelength-sized surface plasmon polariton waveguide caused substantial field concentration, resulting in a spontaneous emission enhancement rate approximately 50 times higher than that of the bulk material. The exceptional characteristics and significantly elevated spontaneous emission enhancement rate of the proposed structure suggest its potential as a single-photon light source. •Unidirectional emission facilitated by different metal surface plasmon polariton.•49-fold enhancement of spontaneous emission rate compared to bulk.•2.8 times greater waveguide coupling efficiency into one end than bare nanowire.