Chiral and quantum optics in 2D platforms

Abstract

A fundamental requirement for photonic technologies is the ability to control the confinement and propagation of light. Widely utilized platforms include 2D optical microcavities in which electromagnetic waves are confined between either metallic or multi-layer distributed Bragg reflector dielectric mirrors. However, the fabrication complexities of thick Bragg reflectors and high losses in metallic mirrors have motivated the quest for efficient and compact mirrors. Recently, 2D transition metal dichalcogenides hosting tightly bound excitons with high optical quality were shown as promising atomically thin mirrors (a, b). In this work, we propose and experimentally demonstrate a sub-wavelength 2D nanocavity using two atomically thin mirrors (c-f). Remarkably, we show how the excitonic nature of the mirrors enables the formation of chiral and tunable cavity modes upon the application of an external magnetic field (g). Our work establishes a new regime for engineering intrinsically chiral sub-wavelength optical cavities and opens avenues for realizing spin-photon interfaces and exploring chiral many-body cavity electrodynamics.