Boosting Strong Coupling in a Hybrid WSe₂ Monolayer–Anapole–Plasmon System

Abstract

The exciton–polaritonic states are generated by the strong interaction between photons and excitons in confined nanocavities. To achieve strong coupling between excitons in TMDCs and optical modes in cavities is quite challenging due to fabrication issues, modal and material dispersion in the cavity, and the weak confinement of the optical field. Hence, investigation of new photonic structures to achieve strong coupling in TMDCs materials is necessary to develop polariton-based devices. Here, we report the observation of the strong coupling between an anapole mode in a slotted silicon nanodisk and an exciton in a WSe2 monolayer, leading to the creation of anapole–exciton polaritons. Furthermore, we have also demonstrated a strong anapole–plasmon and anapole–plasmon–exciton coupling in Si–Ag, and Si–Ag–WSe2 heterostructures, respectively. The observed polaritonic hybrid states have a large Rabi splitting (159 meV) accompanied by high localized field enhancement (157 times increase) in the near field and at a normal incident angle, suggesting a crucial step toward the creation of exciton–polariton nanodevices.

Optical Mode Tuning of Monolayer Tungsten Diselenide (WSe2) by Integrating with One-Dimensional Photonic Crystal through Exciton–Photon Coupling

“…Tungsten diselenide (WSe 2 ) and molybdenum disulfide (MoS 2 ) are two TMDs materials that have been the most investigated in recent years [ 30 , 31 , 32 , 33 , 34 ]. However, MoS 2 has the downside of being easily oxidized in air, resulting in S vacancies in the material, thereby lowering its optical quality [ 35 ].…”

Strong Dipole-Quadrupole-Exciton Coupling Realized in a Gold Nanorod Dimer Placed on a Two-Dimensional Material

“…However, it remains a challenge to realize strong plasmon–exciton coupling with an enhanced coupling strength in a single plasmonic nanostructure on a TMDC monolayer, which can be simply characterized by measuring the scattering spectrum of the nanostructure. Very recently, strong anapole–plasmon–exciton coupling is realized by introducing a plasmonic antenna into a WSe 2 −anapole hybrid system, leading to an enhanced Rabi splitting of ~159 meV [ 45 ]. Unfortunately, complex nanofabrication techniques are necessary for realizing strong coupling in such a hybrid system.…”

Manipulating Optical Scattering of Quasi-BIC in Dielectric Metasurface with Off-Center Hole

“…Another example of multipole interference is the formation of the anapole mode, which has strong near-field enhancement but suppressed far-field radiation. The physical mechanism behind this is the destructive interference of electric dipoles and toroidal dipoles, which shares a similar far-field radiation with the same amplitude and out of phase [ 43 , 44 , 45 , 46 , 47 ].…”