Exciton-Polaritons in monolayer molybdenum disulphide coupled to hyperbolic metamaterial

We report the experimental observation of Exciton-Polaritons in monolayer Molybdenum disulphide (1L-MoS2) coupled to hyperbolic metamaterial (HMM). HMM offers unprecedented control in confining light at sub-wavelength scale and is a versatile platform for coupling emitters. Silver nanowires grown in a porous Alumina film have directional hyperbolic modes along the axis of nanowires. 1L-MoS2 is uniquely suited for coupling to the field of HMM modes, due its in-layer oriented excitonic transition dipole moment. The interaction between MoS2 and HMM might reach strong coupling regime, even with the losses inherent in a plasmonic system like HMM. Mechanically exfoliated 1L-MoS2 was transferred onto the fabricated HMM with a spacer of 10 nm. A double peak feature was observed at the position of MoS2 A exciton in both Photoluminescence (PL) and Absorption spectra. This confirms the strong coupling of 1L-MoS2 Excitons and HMM Plasmon Polaritons and formation of hybrid modes. Low temperature PL was measured to study the dispersion of hybrid Exciton-Polariton modes. Due to scalable fabrication of HMM, our study provides an economical pathway for realizing Polaritons at room temperature.