Strain‐Induced Modification of the Optical Characteristics of Quantum Emitters in Hexagonal Boron Nitride

Quantum emitters in hexagonal boron nitride (hBN) are promising building blocks for the realization of integrated quantum photonic systems. However, their spectral inhomogeneity currently limits their potential applications. Here, tensile strain is applied to quantum emitters embedded in few‐layer hBN films and both red and blue spectral shifts are realized with tuning magnitudes up to 65 meV, a record for any 2D quantum source. Reversible tuning of the emission and related photophysical properties is demonstrated. Rotation of the optical dipole in response to strain is also observed, suggesting the presence of a second excited state. A theoretical model is derived to describe strain‐based tuning in hBN, and the rotation of the optical dipole. The study demonstrates the immense potential for strain tuning of quantum emitters in layered materials to enable their employment in scalable quantum photonic networks. By applying tensile strain to hexagonal boron nitride, the ability to modify the emission energy of embedded quantum emitters, and their corresponding optical properties are demonstrated. Record tuning magnitudes for a 2D material are reported and key insights into the level structure of the atomic defects responsible are discovered. A full theoretical framework is additionally derived to explain the results.