1) Optica Publishes Mini-Review, “Redefining Precision Interferometry and Spectroscopy With High-Performance Optical Interference Coatings”

A cross disciplinary-team of researchers coordinated by Associate Professor Garrett Cole have published a comprehensive mini-review of optical interference coatings in Optica. Including more than 200 references and contributions from experts across the field, the team presents how next-generation optical interference coatings are redefining the limits of precision measurements—pushing the boundaries at the limits of resolving time and space—and applying their technology to a wide variety of research and practical applications.

The review, "Redefining precision interferometry and spectroscopy with high-performance optical interference coatings," brings together decades of advances in low-loss, high-reflectivity mirror coatings and applications that offer astonishing breakthroughs in fields such as optical atomic clocks, gravitational-wave detection, and ultra-sensitive trace-gas sensing. Hailing back to early progress made by leading optical sciences faculty such as Professor Emeritus Angus Macleod, responsible for writing the seminal textbook used for designing similar coatings—this mini-review recognizes the long history and culmination of progress made over the last fifty years by dedicated faculty and student researchers.

Optical interference coatings consist of dozens of nanometer-thin layers engineered to precisely control how light is reflected and transmitted. The review focuses on state-of-the-art high-reflectivity coatings that lose only a handful of photons out of every million, while also minimizing the atomic-scale thermal motion—or “noise,” i.e. “wiggling” of the mirrors. 

The review provides a roadmap for designing quieter, more stable (i.e. less wiggly) mirrors that enable unprecedented precision in measurements of time, distance, and frequency. These enhancements in the technology make measurements that were previously impossible to achieve now completely attainable within the instrument’s limiting error.

Cole, who pioneered crystalline optical coating technology more than 15 years ago, highlights how these coatings have already enabled record-setting laser stability for optical atomic clocks and are being adapted for future gravitational-wave observatories and molecular sensing systems. As these high-performance optical technologies transition from research laboratories into commercial applications, the review serves as a resource for researchers, students, and industry members who are developing next-generation quantum technologies, precision navigation systems, and advanced sensing platforms. 

Read the Mini-Review