Liquid crystal based tailoring of strong coupling in \ch{WS2} metasurfaces: towards reconfigurable quantum photonics

Abstract: Strong light-matter interactions in 2D materials have garnered significant interest for their potential in nonlinear optics and quantum photonics. Transition metal dichalcogenides (TMDCs), with their robust excitonic responses, serve as promising materials for exploring these interactions. Importantly, tailoring such strong coupling giving rise to tunable quantum and non-linear emissions are under explored. In this study, we propose a novel approach that employs liquid crystals (LCs) as a tunable medium to modulate the strong coupling between TMDC excitons and photonic modes and hence gives rise to tunable quantum emissions. LCs offer high birefringence and anisotropic optical properties, which can be dynamically tuned using external stimuli such as electric fields or temperature variations. By embedding TMDCs within an LC environment and coupling them to photonic quasi-bound states in the continuum (quasi-BIC), we demonstrate precise control over the exciton-photon interactions. The orientation of the LCs, governed by applied external fields, directly influences the coupling strength, enabling real-time modulation of exciton-polariton states and Rabi-splitting. Our system exhibits Rabi splitting energy of 182.5 MeV in air, and 139, 153.7, and 131 meV under different LC orientations. Additionally second order autocorrelation function calculated at zero delay yields ( g^{(2)}(0) = 0.89 ), demonstrating photon anti-bunching, confirming the quantum nature of emission. Our findings establish a versatile platform where TMDCs and LCs synergistically enable electrically controllable strong coupling, offering a scalable and responsive architecture for next-generation quantum photonic devices.