Coupling Behavior Of Two-dimensional Layered Material Exciton And Photon In Microcavity

Semiconductor optical microcavities are excellent platform for studying the interaction between light and matter.Studies in the field of cavity quantum electrodynamics have found that the coupling strength between the gain medium and the optical field in the microcavity will cause the excitons to experience different relaxations,thus demystifying the exciton-polariton.At the same time,transition metal dichalcogenides have also caused extensive research due to its unique physical properties,for example,the band gap is changed with its thickness,etc.On this basis,the research on the combination of TMDCs and optical microcavity has been rapidly developed.At present,the most common method is to place TMDCs'monomolecular thin films into optical microcavities to study the exciton-polariton formed after light field strong coupling with the exciton in the monomolecular thin film.However,the conditions for the realization of such quasiparticles are relatively strict,including the low ambient temperature,the high quality of the optical microcavity,the small detuning between the exciton energy of the two-dimensional material and the resonance energy of the optical microcavity.Under the above background conditions,the self-made F-P optical microcavity is used to study the coupling effect between different layers of molecular films of WSe₂ and light field in microcavities in this paper.The main work of this article is as follows:1.Using micro-mechanical peeling method to prepare WSe₂ materials with different thickness,including monolayer,bilayer and thick multilayer film.Then combined with the Ag/SiO₂/Ag optical microcavity structure,the optical coupling control of the luminescent material is realized.2.Detect the properties of materials with different thicknesses transferred into the microcavities by photoluminescence,and study the optical properties of the samples using a microscopic fluorescence/white light reflection spectroscopy system with integrated angle resolution.First,the interaction between the exciton of WSe₂monolayer and the light field in the microcavity was studied at room temperature.The formation of exciton-polariton was found in the strong coupling region,then the experimental phenomena of energy anti-crossing was obtained,and corresponding Rabi splitting energy is 46.7meV.Subsequently,at room temperature,the coupling effect between excitons in the monolayer and bilayer of WSe₂ and the light field in the optical microcavity was detected,and the weak coupling effect occurred.Next,the interaction between the excitons of WSe₂ multilayer and the light field was detected.Because of the weak signal of exciton,experiments were carried out at room temperature?300K?and low temperature?7K?,and the phenomenon of weak coupling was detected in both two conditions.3.Based on the above experimental process,theoretical analysis and simulation calculations are carried out to give more detailed explanation of the interaction between excitons and light field.At the same time,the simulated phenomenon is compared with the experiment to further explain the experimental principle.The purpose of this paper is to control the optical coupling of semiconductor thin film materials in combination with optical microcavity.In a metal microcavity with quality factor of 200 at room temperature?300 K?,the strong coupling between excitons of WSe₂ monomolecular and light field was detected.This phenomenon provides new ideas for some optoelectronic devices and other applications.