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Abstract

Optically addressable spin defects in solids such as diamond nitrogen-vacancy centers have broad applications in quantum sensing and quantum networking. The recent discovery of spin qubits in hexagonal boron nitride (hBN), a van der Waals (vdW) layered material, provides new opportunities for these applications. Thanks to its layered structure, hBN can be easily exfoliated and integrated with other materials and nanostructures. Recently, we demonstrated high-contrast plasmon-enhanced spin defects in hBN for quantum sensing [Nano Letters 21, 7708 (2021)], and investigated their excited-state spin resonance [Nature Commun., 13, 3233 (2022)]. We achieved optical polarization and coherent control of nuclear spins in hBN for the first time [Nature Materials (2022)]. Our work opens new avenues for manipulating nuclear spins in 2D materials for quantum information science and technology. At the end of the talk, I will also briefly mention our recent results in levitated optomechanics [Nature Nanotech. 15, 89 (2020)] and Casimir effects [Nature Nanotech. 17, 148 (2022)].

Biography

Prof. Tongcang Li is a Professor of Physics and Astronomy, and a Professor of Electrical and Computer Engineering at Purdue University. He joined Purdue University as an Assistant Professor in 2014, and was promoted to an Associate Professor in 2020, and promoted to a Full Professor in 2023. He earned his Ph.D. degree from the University of Texas at Austin in 2011, and conducted postdoctoral research at the University of California, Berkeley from 2011-2014. Prof. Li is an expert in quantum sensing and optomechanics. He has won multiple awards, including the NSF CAREER Award in 2016. Prof. Li has published one book and many high-impact papers in Science, Nature Nanotechnology, Nature Physics, Nature Materials, Nature Communications, and other leading journals. His recent work on GHz rotation of an optically levitated nanoparticle was selected as one of the APS Physics “Highlights of the Year” of 2018. His research on on-chip optical levitation with a metalens was included in 30 breakthroughs in “Optics in 2022” by the Optics & Photonics News.