Electrical Control of Guided Exciton‐Polaritons in Atomically Thin Heterostructures at Room Temperature

Abstract Efficient guiding and manipulation of photons at the nanoscale is essential for optical communication and computing. Recent studies have demonstrated that atomically thin 2D semiconductors can function as waveguides even at atomic‐scale thickness, also enabling optical modulation. However, electrical control over guided modes in these atomically thin 2D semiconductors remains largely unexplored. In this report, electrical modulation of guided exciton‐polariton modes within a van der Waals heterostructure composed of an atomically thin tungsten disulfide (WS 2 ) monolayer integrated with hexagonal boron nitride (hBN) is demonstrated. Due to the electrostatic tunability of excitons in monolayer WS 2 , the guided polariton modes in the WS 2 /hBN heterostructure can be electrically modulated. The polariton dispersions in this heterostructure are directly observed under varying gate voltage by using the near‐field coupling technique. Remarkably, the polariton dispersion can be switched off by applying an electrostatic gate voltage of 30 V to optically transparent indium tin oxide (ITO) electrodes. It is believed that this work provides a promising platform for nanoscale polaritonic devices and their integration into on‐chip applications.