OSC Colloquium: Peter de Groot

In a letter from Isaac Newton to Robert Hooke in 1676, we find the famous phrase: “We stand on the shoulders of giants.” Reflecting on my career, I see the wisdom of this profoundly simple statement. After many years working in applied research, I have been granted over 140 US patents on inventions ranging from ultra-precision position sensors to laser radar for measuring the dimensions of airplane wings. At the same time, I am an avid student of the history of optics, and I often tell students that if they would like to become inventors themselves, they should start by reading the old books. Classical works such as Ernst Abbe’s brilliant lectures on optical imaging and Jim Wyant’s insightful papers from the early days of computer-generated holograms are very much alive and relevant today. Many modern discoveries in optics have core concepts dating back decades or even centuries, modernized with new light sources and detectors, and adapted for applications in semiconductor manufacturing and quantum technology that our predecessors could not possibly have imagined.  

These observations raise the intriguing question of what truly constitutes an invention. In this lecture, I share some stories about optical instruments that I would claim are innovative, and others that are perhaps not so novel but are great solutions adapted to new problems. Topics are drawn from coherence scanning interferometry for mapping surface texture, laser Fizeau measurements of optical parts, heterodyne encoders for displacement measurement, interferometric micro-ellipsometry, and high-precision moiré. The goal is to stimulate thoughtful discussion about the role of innovation in advancing the state of the art, building on principles that have been gifted to us by generations of teachers and inventors that have come before us. 

Peter de Groot, PhD, is fascinated by light and its practical use for measuring things. He began his optics career by building a reflecting telescope more than fifty years ago, grinding and polishing the main mirror by hand, and measuring it with the Foucault knife-edge test. Educated first in the liberal arts then in experimental Physics at the Universities of Utah, Grenoble, Maine, and Connecticut, he enjoys discovering the underlying principles and hidden links behind creative work in science and engineering. His research at Perkin Elmer, Boeing, and Zygo Corporation has led to 140 US patents for optical instruments, as well as over 220 technical papers, tutorials, and book chapters. He is a Fellow of Optica, SPIE, the Institute of Physics, and the International Academy of Engineering and Technology. His many awards include a Lifetime Achievement recognition from the American Society for Precision Engineering. An experienced teacher and lecturer worldwide, he is a short-course instructor, honorary professor, and returned Peace Corps volunteer.  

Peter is currently Scientist Emeritus at Zygo Corporation, and served in 2025 as President of SPIE, the International Society for Optics and Photonics.