Kavli Nanoscience Institute Special Lecture: 10 years of the KNI-Wheatley Scholarship in Nanoscience

Andrei Faraon (BS '04) will deliver a special lecture as part of the 2026 Caltech Alumni Reunion Weekend. Faraon is William L. Valentine Professor of Applied Physics and Electrical Engineering and Fletcher Jones Foundation Director of the Kavli Nanoscience Institute.

This lecture commemorates the tenth anniversary of the KNI-Wheatley Scholarship in Nanoscience, which was made possible through the generous donation by Chuck (BS '56) and Judy Wheatley. As the inaugural recipient in 2016, Dr. Faraon's talk will cover his research trajectory over the past ten years to present day challenges and what lies ahead.

Join us for light refreshments at 10 am. Lecture will begin at 10:30 am.

"Building a quantum internet one atom at a time: rare earth ions and nanophotonics"

Abstract

Quantum technologies promise computers that can tackle problems beyond the reach of today's machines, communication networks whose security is guaranteed by the laws of physics, and sensors of unprecedented precision. Building them requires quantum bits (qubits) that can preserve fragile quantum states long enough to be useful, and a way to link these qubits over long distances using light. In this talk I describe how my group uses rare earth ions, the same elements that power many lasers, displays, and permanent magnets, as qubits embedded in crystals. The spins of their electrons and nuclei behave like tiny magnets that can store quantum information for remarkably long times, while the ions themselves absorb and emit light that can be sent through optical fibers. By trapping light in optical cavities smaller than a human hair is wide, carved directly into the crystal, we can detect and control individual ions, one atom at a time. I will show how we use these ions to create quantum entanglement between distant nodes of a quantum network, to store quantum information in the surrounding nuclear spins, to convert quantum signals between the microwave frequencies used by superconducting quantum computers and the optical frequencies used in fiber communication, and to study the collective behavior of large ensembles of interacting quantum spins. I will conclude with an outlook on how these building blocks could come together into a future quantum internet.

Selected references:

[1] Andrei Ruskuc, Chun-Ju Wu, Emanuel Green, Sophie L. N. Hermans, Will Pajak, Joonhee Choi, Andrei Faraon, Multiplexed entanglement of multi-emitter quantum network nodes, Nature, volume 639, pages 54–59 (2025)

[2] Andrei Ruskuc, Chun-Ju Wu, Jake Rochman, Joonhee Choi, Andrei Faraon, Nuclear spin-wave quantum register for a solid state qubit, Nature, 602, 408–413 (2022)

[3] Tian Xie, Rikuto Fukumori, Jiahui Li, Andrei Faraon, Scalable microwave-to-optical transducers at single photon level with spins, Nature Physics, volume 21, pages 931–937 (2025)

[4] Mi Lei, Rikuto Fukumori, Chun-Ju Wu, Edwin Barnes, Sophia Economou, Joonhee Choi, Andrei Faraon, Quantum thermalization and Floquet engineering in a spin ensemble with a clock transition, Nature Physics, https://doi.org/10.1038/s41567-025-02943-4 (2025)

Biography

Dr. Andrei Faraon is the William L. Valentine Professor of Applied Physics and Electrical Engineering and the Fletcher Jones Director of the Kavli Nanoscience Institute at California Institute of Technology. After earning a B.S. degree in physics with honors in 2004 at California Institute of Technology, he received his M.S. in Electrical Engineering and PhD in Applied Physics both from Stanford University in 2009. From 2009 to 2012 he was a postdoctoral fellow at Hewlett Packard Laboratories. During his PhD he was involved in seminal quantum optics experiments using single semiconductor quantum dots coupled to photonic crystal resonators. At HP, he pioneered quantum nano-photonic devices in single crystal diamond coupled to color centers.

Dr. Faraon left HP in 2012 for a faculty position at Caltech where he works on nano-photonic technologies for both classical and quantum applications including: optically addressable quantum bits, optical quantum memories, microwave to optical quantum transduction, metasurfaces and metamaterials for multi-functional imaging applications.

Dr. Faraon is the recipient of the 2018 Adolph Lomb Medal of Optica that recognizes a noteworthy contribution to optics made by a researcher who is still early in his or her career, and was elected as Optica Fellow in 2020.