Invited Speakers

Paul Williams

Project Lead - High Power Laser Applications, National Institute of Standards and Technology (NIST)
Tuesday, August 31, 2021

Using Photon Momentum to Measure Optical Power with a Mirror Rather than an Absorber

Light carries momentum. And that momentum is linearly related to its optical power. For over a century, this relationship has been used to demonstrate instruments that use radiation pressure to measure optical power. However, only in the last decade or so have such power meters become practical tools. I will talk about our development at NIST of primary-standard radiation pressure power meters and the benefits of measuring optical power with a mirror instead of an absorber. This story will be used as a case study to describe nerdy metrology concepts like “NIST traceability” and standards development.

Paul Williams leads the “High Power Laser Applications Project” at the National Institute of Standards and Technology in Boulder, Colorado. His team works to develop measurement methods for high power lasers for manufacturing, defense, and research. His background is in high accuracy metrology of laser power, polarization, fiber optics, optical frequency combs, interferometry, liquid crystals, and electro-optic phenomena.