Abstract

In 2018 Arthur Ashkin was awarded a half share of that year’s Nobel Prize in Physics “for the optical tweezers and their application to biological systems”. The work for which he was recognised had its origins more than thirty years before, and in the years since their invention, the uses of optical tweezers have grown far beyond biological systems, with numerous diverse applications across the chemical and physical sciences also. In this lecture we will look at the history of our understanding of the force that light exerts on matter, which has its origins in the observations of Johannes Kepler concerning the tails of comets. We will see how the concept of radiation pressure evolved from the work of James Clerk Maxwell, and trace its development to the experiments in which Arthur Ashkin first demonstrated the optical tweezers. Finally, we will examine just a few of the many uses of optical tweezers where their ``light touch’’ and ability to trap a single microscopic particle and isolate it from its surroundings have proved invaluable.

Philip Jones is a physicist whose research centres on optical trapping and its use as a tool for probing a variety of nanoscopic, soft matter and biological materials. He is currently Professor of Physics at University College London where he leads the Optical Tweezers Group. Recently he has co-authored the first textbook on optical tweezers, published by Cambridge University Press.