Humboldt-Universität zu Berlin - Faculty of Mathematics and Natural Sciences - Department of Physics

Department Colloquium: Prof. David L. Andrews (University of East Anglia, UK) will speak about "Push and Pull, Twist and Turn: Photons Give a Hand".

Abstract

It is well known that light has a capacity to generate forces – a principle already widely used in 'laser tweezers'. As each quantum of light conveys a momentum that can engage with matter, attention is increasingly being focused on pursuing these principles in the nanoscale regime, with the manipulation of nanoparticles and large molecules now a realistic prospect. Photons can deliver spin angular momentum too, providing torque. Advances in structured light offer many further avenues of application, as photons can also convey orbital angular momentum. Some recent studies raise the possibility of discriminating between molecules of opposite handedness, or steering individual molecules to separate those of opposite chiral form. To understand such interactions is challenging, as quantum features emerge in both the matter and the light itself. This talk shows how photons can drive motion, and quantum fluctuations can also generate exotic nanoscale forces.