Title: Rings of Light: Nonlinear Optics in the Age of Integration
Author: Professor Kerry Vahala, Caltech
Date: Tuesday, November 10, 2026, 4 PM (3:30 for refreshments)
Place: 1101 A. James Clark Hall, 8278 Paint Branch Drive, College Park, MD 20742
Abstract: Light can be trapped and stored in microscopic rings of transparent materials, circulating millions of times at a discrete set of resonant frequencies. In these tiny structures, photons linger far longer than intuition would suggest, turning simple rings into extraordinary reservoirs of optical energy. Over the past several decades, advances in fabrication and design have pushed this photon recycling to unprecedented extremes. What began as a curiosity in resonant optics has evolved into a powerful new platform for nonlinear optics, ultra-stable lasers, and precision measurement. After a brief look back at the origins of these devices and the earliest nonlinear demonstrations, this talk will survey recent breakthroughs in ring-resonator technology and systems. A central theme will be the miniaturization of precision metrology to the chip scale: frequency synthesis, optical clocks, and microwave signal generation built from optical frequency microcombs. Integrated routes to highly coherent visible and near-visible light sources will also be highlighted. Finally, we look ahead to the transformative measurement and sensing systems enabled by these tiny rings of light.
Biography: Kerry Vahala has pioneered nonlinear optics in high-Q optical microresonators, helping to establish a new field in modern photonics. His work includes the first demonstration of parametric oscillation and cascaded four-wave mixing in a microcavity—the central regeneration mechanisms underlying optical frequency microcombs—and the earliest demonstrations of these devices in optical clocks, frequency synthesis, spectroscopy, and astrocombs. Vahala is a Professor of Applied Physics and the Jenkins Professor of Information Science and Technology. He is a member of the National Academy of Engineering and a Fellow of both IEEE and Optica. His other honors include the Charles Hard Townes Medal from Optica for work on microresonators and nonlinear oscillators; the IEEE David Sarnoff Medal for research on quantum-well laser dynamics; the Alexander von Humboldt Award for advancements in ultra-high-Q optical microcavities; a NASA Achievement Award for the application of microcombs to exoplanet detection; and the Optica Paul F. Forman Team Engineering Excellence Award for the development of a two-photon optical clock.
Paint Branch is a 14-mile stream that brings water from small streams and tributaries throughout the region, flowing south through our campus on its way to the Anacostia River. Many of us pass it by car, bicycle, or on foot each day on our way to and from work. Like the Paint Branch, we anticipate that this new lectureship will serve as a confluence that draws together the many talented and active researchers, faculty, and students in applied physics in our community and will remind us of our common goals and principles.
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