Marko Lončar, Harvard University, This email address is being protected from spambots. You need JavaScript enabled to view it.
As quantum information technology matures and becomes more complex, so do the needs for interconnecting disparate quantum subsystems (computers, networks, sensors) into larger quantum networks. Thus, developing reliable quantum interconnects (QuICs) – from chip- to continental-scale, is emerging as one of the central goals for quantum information science and technology. I will describe our activities aimed at realization of two important QuICS: quantum repeaters (QR) and quantum transducers (QT). Our QRs rely on silicon-vacancy (SiV) color center in diamond, a leading quantum memory platform, essential for realization of long-distance quantum networks [1]. In addition to their excellent spin and optical properties, SiVs feature large strain susceptibility [2] which has resulted in emergence of the field of quantum phononics. Here, phonons could be used to control SiVs [3-5] as well as to realize chip-scale QuICs. I will also discuss our work on thin film lithium niobate (TFLN) photonic platform [6] that can be used to control spectral and temporal [7, 8] properties of photons emitted by SiVs. Finally, QTs based on TFLN [9] will also be presented. These devices can enable realization of networks of quantum computers, connected with low loss and low noise optical communication channels.
Kay Boardrooms (1107/1111) in the Kim Engineering Bldg.
For those unable to attend in person, a Zoom link is provided below.
Biography: Marko Lončar is Tiantsai Lin Professor of Electrical Engineering at Harvard's John A Paulson School of Engineering and Applied Sciences (SEAS). Lončar received his Diploma from University of Belgrade (R. Serbia) in 1997, and PhD from Caltech in 2003 (with Axel Scherer), both in Electrical Engineering. After completing his postdoctoral studies at Harvard (with Federico Capasso), he joined Harvard faculty in 2006. Lončar is expert in nanophotonics and nanofabrication, and his group has done pioneering work in the field of quantum and nonlinear nanophotonics. In particular, Lončar is recognized for his work on the development of diamond and thin film lithium niobate nanophotonic platforms. Lončar has co-authored more than 250 manuscripts in top scientific journals and has given more than 300 invited talks and seminars. He has received NSF CAREER Award in 2009, Sloan Fellowship in 2010, Marko Jarić Foundation Award in 2020, and Microoptics Conference Award in 2023. In recognition of his teaching activities, Lončar has been awarded Harvard University Levenson Prize for Excellence in Undergraduate Teaching (2012), and has been named Harvard College Professor in 2017. Lončar is Fellow of Optical Society of America and IEEE, as well as Senior Member of SPIE. He is co-founder of HyperLight Corporation (Cambridge, MA), VC backed startup commercializing lithium-niobate technology developed in his lab.
1. M.Bhaskar, et al, “Experimental demonstration of memory-enhanced quantum communication” Nature, 580, 60 (2020); 2. Y. I. Sohn*, Srujan S. Meesala*, B. Pingault*, H. A. Atikian, J. Holzgrafe, M. Gündoğan, C. Stavrakas, M. J. Stanley, A. Sipahigil, J. Choi, M. Zhang, J. L. Pacheco, J. Abraham, E. Bielejec, M. D. Lukin, M. Atatüre, and M. Lončar. “Controlling the coherence of a diamond spin qubit through its strain environment.” Nature Communications 9, 2012 (2018) 3. S. Maity, L. Shao, S. Bogdanović, S. Meesala, Y. I. Sohn, N. Sinclair, B. Pingault, M. Chalupnik, C. Chia, L. Zheng, K. Lai, and M. Lončar, “Coherent Acoustic Control of a Single Silicon Vacancy Spin in Diamond.” Nature Communications, 11, 1, Pp. 193 (2020) 4. G. D. Joe, M. Haas, K. Kuruma, C. Jin, D. Kang, S. Ding, C. Chia, H. Warner, B. Pingault, B. Machielse, S. Meesala, and M. Lončar. “Observation of the acoustic Purcell effect with a colorcenter and a nanomechanical resonator”, arXiv: 2503.09946 (2025) 5. K. Kuruma, B. Pingault, C. Chia, M. Haas, G. D. Joe, D. R. Assumpcao, S. W. Ding, C. Jin, C. J. Xin, M. Yeh, N. Sinclair, and M. Lončar, “Engineering Phonon-Qubit Interactions using Phononic Crystals.” Nature Physics, 21, 77 (2025) 6. D. Zhu, L. Shao, M. Yu, R. Cheng, B. Desiatov, C. J. Xin, Y. Hu, J. Holzgrafe, S. Ghosh, A. ShamsAnsari, E. Puma, N. Sinclair, C. Reimer, M. Zhang, and M. Lončar. “Integrated photonics on thinfilm lithium niobate.” Advances in Optics and Photonics, 13, 242 (2021) 7. D. Renaud, D. R. Assumpcao, G. Joe, A. Shams-Ansari, D. Zhu, Y. Hu, N. Sinclair, and M. Lončar, “Sub-1 Volt and high-bandwidth visible to near-infrared electro-optic modulators”, Nature Communications, 14, 1496 (2023) 8. D. Assumpcao, D. Renaud, A. Baradari, B. Zeng, C. De-Eknamkul, CJ Xin, A. Shams-Ansari, D. Barton, B. Machielse, M. Loncar, “A Thin Film Lithium Niobate Near-Infrared Platform for Multiplexing Quantum Nodes” Nature Communications, 10459 (2024) 9. H. K. Warner, J. Holzgrafe, B. Yankelevich, D. Barton, S. Poletto, C. J. Xin, N. Sinclair, D. Zhu, E. Sete, B. Langley, E. Batson, M. Colangelo, A. Shams-Ansari, G. Joe, K. K. Berggren, L. Jiang, M. Reagor, and M. Loncar. “Coherent control of a superconducting qubit using light.” Nature Physics, 21, 831 (2025)