"Strain and Defects in 2D Materials: Quantum Light Emission and Nanoscale Sensing"

Presented by Dr. Huan Zhao, Distinguished Staff Fellow from the Center for Nanophase Materials Sciences (CNMS) at the Oak Ridge National Laboratory

A scalable, long-range quantum internet will hinge on high-performance photonic qubits for secure communication, distributed computing, and advanced sensing. I will show how strain and defect engineering in 2D materials enables deterministic control of spin and excitonic degrees of freedom for quantum light emission and sensing. I will briefly survey our near-infrared—especially telecom-band—single-photon emitters realized in monolayers, multilayers, and heterostructures, with emission tuned by strain, defect species, and layer number. The second half focuses on diamond NV–based single-spin (T₁) relaxometry as a general, largely all-optical route to discover, quantify, and map spin-active defects in 2D materials with nanoscale resolution, exemplified by boron vacancies in hBN; this platform also enables heterogeneous quantum architectures by decoupling sensing and readout into distinct qubits to exploit complementary strengths. All work was conducted at the Center for Nanophase Materials Sciences (CNMS), a U.S. Department of Energy Office of Science user facility at Oak Ridge National Laboratory; I will also briefly introduce CNMS capabilities and how to prepare a user proposal.