High-contrast switching and high-efficiency extracting for spontaneous emission based on tunable gap surface plasmon

Abstract

Controlling spontaneous emission at optical scale lies in the heart of ultracompact quantum photonic devices, such as on-chip single photon sources, nanolasers and nanophotonic detectors. However, achiving a large modulation of fluorescence intensity and guiding the emitted photons into low-loss nanophotonic structures remain rather challenging issue. Here, using the liquid crystal-tuned gap surface plasmon, we theoretically demonstrate both a high-contrast switching of the spontaneous emission and high-efficiency extraction of the photons with a specially-designed tunable surface plasmon nanostructures. Through varying the refractive index of liquid crystal, the local electromagnetic field of the gap surface plasmon can be greatly modulated, thereby leading to the swithching of the spontaneous emission of the emitter placed at the nanoscale gap. By optimizing the material and geometrical parameters, the total decay rate can be changed from 103γ0 to 8750γ0, [γ0 is the spontaneous emission rate in vacuum] with the contrast ratio of 85. Further more, in the design also enables propagation of the emitted photons along the low-loss phase-matched nanofibers with a collection efficiency of more than 40%. The proposal provides a novel mechanism for simultaneously switching and extracting the spontaneous emitted photons in hybrid photonic nanostructures, propelling the implementation in on-chip tunable quantum devices.

Topologically Enabled Ultralarge Purcell Enhancement Robust to Photon Scattering

“…At the edge state of λ=722.4 nm, which is also corresponding to the resonant wavelength of Ag nanoantenna, there is a dip in the spectra of γ tot /γ 0 and γ ab /γ 0 , and γ tot /γ 0 is in its minimum while the γ ed /γ 0 reaches its maximum. This ultralarge nonscattering enhancement superior to that of gap surface plasmon structures, where the Purcell factor is also very large, but the guided part is relatively small and the stray light exists [10][11][12]. The linewidth of γ ed /γ 0 is greatly less than that of γ tot /γ 0 due to the decoupling bewteen the 1D PC and Ag nanorod.…”

“…A quantum emitter is set at the nanoscale gap of antenna. To compute the Purcell factors of above topological structure, 3D finite-element simulations were performed using COMSOL Multiphysics software, through which we have simulated optical modes, Purcell enhancement, photon collection, and photon-emitter coupling strength for various photonic structures [10][11][12][38][39][40]. To simulate the infinite 1D PC, periodic boundary condition is applied for the vertically directional boundary of propagation.…”

“…However, their scattering and absorption are two barriers when guiding these single photons into other devices. To solve the problem of scattering, the gap surface plasmon structures are proposed by combining the advantages of effectively collecting scattering light by a nanowire or nanofilm and inducing large Purcell enhancement by plasmon nanoparticles [10][11][12]. However, their collecting efficiency is not very high and it is almost impossible to reach 100% collecting of photons.…”

Nanoantenna‐Enhanced Light‐Emitting Diodes: Fundamental and Recent Progress

“…Compared to metallic nanoantennas, dielectric nanoantennas are more power efficient due to their low‐loss characteristic, which could naturally suppress the nonradiative decay. [ 83,84 ] Meanwhile, dielectric nanoantenna could also generate resonance modes upon incident light illumination, producing local electric field enhancement at the vicinity of nanoantenna. [ 85,86 ] On top of that, dielectric nanoantenna could generate both electric and magnetic types of resonance mode depending on the displacement current distribution inside the nanoantenna ( Figure a), whereas the metallic nanoantenna is, in general, dominated by the electric type of the resonance.…”

Quantum State Transfer with Seamless Frequency‐Connection Through Diamond Optomechanical Cavity

“…Specifically, we assume that the nanofiber with refractive index has the rectangular cross section, whose structural parameter size is nm, nm. [ 38,39 ] As shown in Figure 1b, the spin state in the first node can be mapped onto the cavity photon state via the phonon, and then be translated away through the nanofiber and mapped to cavity photon again in another node. Later, after the reverse operation, the information carried by spin state in the first node can be transferred to spin state in the second node.…”