Tunable quantum confinement of excitons using electric fields and exciton-charge interactions

Achieving fully tunable quantum confinement of optical excitations such as excitons has been a long-standing goal in optoelectronics and quantum photonics. In this talk, we will discuss our recent experimental results demonstrating, for the first time, electrically controlled 1D quantum confinement of neutral excitons in a monolayer transition metal dichalcogenide semiconductor. This confinement relies on a combination of dc Stark effect induced by inhomogeneous in-plane electric fields and a novel polaronic confinement mechanism arising from interactions between excitons and itinerant charge carriers. Quantization of excitonic motion shows up in optical spectroscopy as discrete gate voltage-dependent, energy-split lines. We will also discuss some future prospects of these electrically confined in-plane dipolar excitons. First, electrical confinement of excitons with in-plane dipole moment is expected to enhance exciton-exciton interactions while allowing for hybridization with a microcavity mode. Strong interactions in a 1D wire could enable the realization of a Tonks-Girardeau gas with photon correlations providing signatures of fermionization. Furthermore, proper design of gate electrodes may enable novel confinement geometries such as quantum dots, wires and rings. We anticipate that such electrically quantum confined excitons could become building blocks for scalable arrays of identical, independently tuned quantum emitters and have implications for ongoing efforts towards realizing strongly correlated photonic systems.