Yueh-Chun Wu received his Ph.D. in 2023 from the University of Massachusetts Amherst, where he studied the optical spectroscopy of valley dynamics of excitons in van der Waals heterostructures. He is currently a postdoctoral researcher at Oak Ridge National Laboratory, where he investigates solid-state defects as quantum sensing probes and quantum emitters. His research focuses on developing quantum sensing techniques to understand emergent charge and spin orders in quantum materials, particularly two-dimensional magnets and correlated electron systems in van der Waals heterostructures.
Presentation Title:
Quantum Defects Meet Quantum Materials: Engineering hBN Spin Ensembles for Relaxometry Quantum Sensing
Presentation Abstract:
Atomic defects in layered boron nitride (BN) have attracted growing interest as potential solid-state quantum light sources and sensors, yet their microscopic origin and coupling to the host lattice often remain elusive. Here, we study blue-emitting defects in BN using isotope and stacking engineering, combined with spatially correlated photoluminescence, Raman, and second-harmonic-generation measurements. We analyze the spectral and polarization characteristics of the zero-phonon lines and phonon sidebands, with particular attention to phonon-sideband energy shifts and changes in polarization angle. These signatures reveal how the optical transition couples to lattice vibrations and local crystal symmetry. We further examine the roles of isotope composition, stacking configuration, and structural environment in determining the emission properties. Our results establish correlations among quantum-emitter characteristics, phonon coupling, and crystal structure in engineered layered BN, placing new constraints on the microscopic origin of the emitters. More broadly, this work demonstrates isotope and stacking engineering as promising approaches for understanding and tailoring quantum emitters in layered materials.