Fall 2026 Colloquia

How is it possible that 1/4 of the Nobel Prizes in Physics since 2006 have been for astrophysics? All 5 of them came from new technologies, and two required space observatories. I’ll review the breakthrough ideas that grew into discoveries, and suggest where future technologies might go.

The JWST is working brilliantly, and has found Little Red Dots, the current mystery object. But there’s still no Earth 2.0. The DKIST solar telescope with adaptive optics is working beautifully. The Vera Rubin Telescope is online, the Nancy Grace Roman Space Telescope will be launched just before this colloquium to study dark matter, dark energy, and exoplanets, and the 39 m diameter Extremely Large Telescope will be doing science around 2030. Among the new possibilities: the Habitable Worlds Observatory, a workhorse UV-near IR observatory with a coronagraph for exoplanets, and X-ray and far IR observatories from Probe class ($1B) to flagships. New detector and mirror technologies are making both exciting. The NAUTILUS concept will use molded glass lenses up to 8 m in diameter in space to collect light for spectroscopy.

We’re also developing hybrid observatories combining telescopes and interferometers on the ground with satellites. The Landolt absolute photometric calibrator beacon will fly in 2029, and the CELESTE mission is a proposed Small Explorer to offer a laser beacon for adaptive optics to the ELT, giving it diffraction-limited image quality at visible wavelengths where the sky is darkest. An orbiting starshade could cast a star shadow on the ELT and enable imaging of another Earth in one minute. The Black Hole Explorer would extend the Event Horizon Telescope with an orbiting antenna could measure the spin of a black hole. If you can imagine it, you can build it.

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.