Dr. Huan Zhao is a research scientist at Oak Ridge National Laboratory (ORNL), where he leads interdisciplinary work in spin-based quantum sensing, solid-state quantum light sources, nanomaterials, optical imaging, and nanoelectronics. He earned his Ph.D. in Electrical Engineering from the University of Southern California in December 2019. From 2019–2022, he was a Director’s Postdoctoral Fellow at the Center for Integrated Nanotechnologies, Los Alamos National Laboratory. He then joined the Caltech Optical Imaging Lab as a postdoctoral scholar before moving to ORNL in December 2023. His current work focuses on advancing quantum materials and technologies for next-generation sensing, communication, and imaging applications. His contributions to quantum photonics have been recognized with honors including the Wigner Fellowship, the CNMS Division Award, and the Nanophotonics Early Career Award.
Presentation Title:
Probing Spin Defects via Single Spin Relaxometry
Presentation Abstract:
Spin defects in solids provide long-lived quantum states ideal for sensing and information storage. We integrate a single nitrogen-vacancy (NV) center in diamond with scanning probe microscopy to discover, read out, and spatially map nanoscale spin-based quantum sensors. Using the boron vacancy (VB−) center in hexagonal boron nitride as a model system, we indirectly detect its electron spin resonance by monitoring changes in the NV center’s spin relaxation time (T1), eliminating the need for optical excitation or fluorescence detection of VB−. Cross-relaxation between NV and VB− ensembles significantly shortens NV T1, enabling quantitative mapping of defect densities beyond the optical diffraction limit and resolving hyperfine splitting in isotopically enriched h10B15N. Our approach demonstrates robust interactions between 3D and 2D spin sensors, establishing NV centers as versatile probes to characterize otherwise inaccessible spin defects.