2,064 research outputs found
High-Q exterior whispering gallery modes in a metal-coated microresonator
We propose a kind of plasmonic whispering gallery modes highly localized on
the exterior surface of a metal-coated microresonator. This exterior (EX)
surface mode possesses high quality factors at room temperature, and can be
efficiently excited by a tapered fiber. The EX mode can couple to an interior
(IN) mode and this coupling produces a strong anti-crossing behavior, which not
only allows conversion of IN to EX modes, but also forms a long-lived
anti-symmetric mode. As a potential application, the EX mode could be used for
a biosensor with a sensitivity high up to 500 nm per refraction index unit, a
large figure of merit, and a wide detection range
Quantum electrodynamics in a whispering-gallery microcavity coated with a polymer nanolayer
Quasi-transverse-electric and -transverse-magnetic fundamental whispering
gallery modes in a polymer-coated silica microtoroid are theoretically
investigated and demonstrated to possess very high-quality factors. The
existence of a nanometer-thickness layer not only evidently reduces the cavity
mode volume but also draws the maximal electric field's position of the mode to
the outside of the silica toroid, where single quantum dots or nanocrystals are
located. Both effects result in a strongly enhanced coherent interaction
between a single dipole (for example, a single defect center in a diamond
crystal) and the quantized cavity mode. Since the coated microtoroid is highly
feasible and robust in experiments, it may offer an excellent platform to study
strong-coupling cavity quantum electrodynamics, quantum information, and
quantum computation
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