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Brightening and Guiding Single‐Photon Emission by Plasmonic Waveguide–Slit Structures on a Metallic Substrate
Author(s) -
Zhang Guorui,
Jia Shangtong,
Gu Ying,
Chen Jianjun
Publication year - 2019
Publication title -
laser and photonics reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.778
H-Index - 116
eISSN - 1863-8899
pISSN - 1863-8880
DOI - 10.1002/lpor.201900025
Subject(s) - plasmon , surface plasmon polariton , materials science , nanowire , substrate (aquarium) , surface plasmon , waveguide , figure of merit , optoelectronics , dielectric , optics , physics , oceanography , geology
By designing a plasmonic waveguide–slit structure (a nanoslit etched in a silver nanowire) on a silver substrate, an ultrahigh Purcell factor and ultralarge figure of merit (FOM) are numerically predicted. Because of the large field enhancement (>150 times the incident field) and the ultrasmall optical volume ( V ≈ 2 × 10 −5 λ 3 ) of the resonant mode in the metallic nanoslit, the simulations show that the Purcell factor in the system can reach up to F P = 1.68 × 10 5 , which is more than ten times the maximum Purcell factor in previous work (by placing metallic nanoparticles on a metal surface with a nanogap). Because of the utilization of a silver substrate rather than the common dielectric substrate, the mode cutoff of the surface plasmon polariton (SPP) waveguide mode is completely eliminated, which provides a large selection range of the nanowire radii to support the resonant mode in the nanoslit. Moreover, the SPP propagation length is significantly increased by more than 30 times. As a result, an ultralarge FOM of 1.40 × 10 7 is obtained, which is more than 80 times the maximum FOM in previous work where the metallic nanowire is placed on or surrounded by dielectric materials.