Coupling of Photon Emitters in Monolayer WS<sub>2</sub> with a Photonic Waveguide Based on Bound States in the Continuum
Xiaojing Liu, Yue Yu, Di Liu, Qilong Cui, Xiao‐Zhuo Qi, Yang Chen, Guangyuan Qu, Li Song, Guo‐Ping Guo, Guang‐Can Guo, Xiankai Sun, Xi‐Feng Ren
Abstract
On-chip light sources are an essential component of scalable photonic integrated circuits (PICs), and coupling between light sources and waveguides has attracted a great deal of attention. Photonic waveguides based on bound states in the continuum (BICs) allow optical confinement in a low-refractive-index waveguide on a high-refractive-index substrate and thus can be employed for constructing PICs. In this work, we experimentally demonstrated that the photoluminescence (PL) from a monolayer of tungsten sulfide (WS 2 ) could be coupled into a BIC waveguide on a lithium-niobate-on-insulator (LNOI) substrate. Using finite-difference time-domain simulations, we numerically obtained a coupling efficiency of ∼2.3% for an in-plane-oriented dipole and a near-zero loss at a wavelength of 620 nm. By breaking through the limits of 2D-material integration with conventional photonic architectures, our work offers a new perspective for light–matter coupling in monolithic PICs.