Electrical Engineering Seminars

Creating the Next Generation of Diamond-based Quantum Technologies with Heterogeneous Membrane Integration

Alexander High, Assistant Professor of Molecular Engineering, University of Chicago

Thursday, Dec 7, 2023

The continued evolution of quantum technologies in diamond requires heterogenous material platforms for sophisticated functionalities, device integration and packaging, and improved qubit performance. At UChicago and Argonne National Laboratory, we are creating pristine single-crystal diamond membranes that host coherent color center qubits and integrating them with a wide range of materials including fused silica, sapphire, thermal oxide, lithium niobate, tantalum, silicon and YIG. The membrane uniformity and robustness to fabrication enables several varieties of integrated nanophotonic cavities – critical elements in quantum photonics - with record quality factors. Furthermore, we show that our ultra-thin diamond membranes are compatible with total internal reflection fluorescence (TIRF) microscopy, which enables interfacing coherent diamond quantum sensors with living cells while rejecting unwanted background luminescence. Remarkably, we demonstrate that membrane integration can improve the spin coherence and microwave addressability of tin vacancy qubits while maintaining exceptional optical coherence, allowing us to create an operational spin-photon interface at 4 Kelvin. In total, the combination of qubit performance, high-performance device fabrication, and flexible materials integration will enable a broad range of quantum photonic, acoustic, and sensing science and technologies. We will also demonstrate that color centers can function as optical antennas that can efficiently concentrate optical energy in solids, with up to million-fold local intensity enhancement under resonant excitation, and discuss potential applications in spectroscopy, sensing, and quantum science.


Speaker Bio

Prof. High studies solid state quantum and optical science. He explores methods to integrate, structure, and control quantum materials to create new technologies and explore new regimes in physics. Currently, his lab is developing quantum technologies in diamond membranes, and exploring physics and technologies of excitons and correlated electrons in 2D materials. Prof. High received his Ph.D. at the University of California San Diego, followed by a postdoctoral fellowship at Harvard University. He joined the University of Chicago as an assistant professor in 2017.



Flavio Calmon


Jessica Brenn