Strong coupling with directional absorption features of Ag@Au hollow nanoshell/J-aggregate heterostructures

Abstract

Tunable plasmon-exciton coupling is demonstrated at room temperature in hybrid systems consisting of Ag@Au hollow nanoshells (HNSs) and J-aggregates. The strong coupling depends on the exciton binding energy and the localized surface plasmon resonance strength, which can be tuned by changing the thickness of the Ag@Au HNS. An evident anticrossing dispersion curve in the coupled energy diagram of the hybrid system was observed based on the absorption spectra obtained at room temperature. In this paper, strong coupling was observed twice (first at lower wavelength and then also at a higher wavelength) via a single preparation process of the Ag@Au HNS system. The first Rabi splitting energy (ħΩ) is 225 meV. Then, the extinction spectra of the bare Ag@Au HNS and the Ag@Au HNS-J-aggregate hybrid system were reproduced by numerical simulations using the finite-difference time domain method, which were in good agreement with the experimental observations. We attributed the strong coupling of the new shell hybrid system to the reduced local surface plasmon (LSP) mode volume of the Ag@Au HNS. This volume is about 1021.6 nm3. The features of the Ag@Au HNS nanostructure with a small LSP mode volume enabled strong light-matter interactions to be achieved in single open plasmonic nanocavities. These findings may pave the way toward nanophotonic devices operating at room temperature.

Plasmon–Exciton Interactions: Spontaneous Emission and Strong Coupling

“…The Rabi splitting is about 120 meV for the dipole mode and about 100 meV for the quadrupole mode. Similar observations were reported in the coupling systems of J-aggregates and Au nanostars, [315] Ag nanoprisms, [316,317] Au nanorods, [318,319] Ag@Au hollow nanoshells, [320] Au@Ag nanorods, [321][322][323] Ag-Au nanorings, [324] etc. Spectral splitting was observed in both the extinction and PL spectra for the hybrid system of J-aggregates and Au nanorods.…”

Exciton–Photonics: From Fundamental Science to Applications

“…(A) Comparison of different cavity mode (microcavity, resonator, photonic cavity, and micropillars) shows that the plasmonic cavity can achieve strong coupling at 300 K due to its ultrasmall mode volume despite a low Q factor. (B) Excitonic materials, namely, QDs, ,− organic molecules (0D), − SWCNTs, − perovskites (1D), − J-aggregates, − , 2D HOIP, − 2D TMDC monolayers, − and 3D TMDC multilayers ,,− studied in cavity mode. Rabi splitting (ℏΩ) to transition dipole moment (μ) as a figure of merit (ℏΩ/μ) is compared for these excitonic materials.…”

Room-temperature plexcitonic strong coupling: Ultrafast dynamics for quantum applications

“…In the past decade, the attention has been shifted from exploiting collective plasmons in NP arrays to reducing the mode volume of single NPs to enhance the interaction with individual quantum emitters. Example configurations of single NPs include core-shell nanospheres 33,42 [Fig. 1(c)], nanoprisms 34,[43][44][45] [Fig.…”