School of Mathematical Sciences Waves and PDEs Colloquium

Speaker: Professor Sir Michael Berry, FRS (University of Bristol) 
Time and location: 3pm, Friday 1 May, Aula Maxima

Title: A plurality of optical singularities: intensity, phase, polarisation

Abstract: In modern optics, we understand fields of light through their geometrical singularities. These are different at different levels of description. The coarsest level is geometrical optics, where the singularities are caustics: focal lines and surfaces. These singularities of bright light are classified by the mathematics of catastrophe theory. Wave optics smooths these singularities and decorates them with rich and ubiquitous interference patterns. Wave optics also introduces phase, which has its own singularities. These are optical vortices, a.k.a nodes or wavefront dislocations. Geometrically, these singularities of dark light are lines in space, or points in the plane. They occur in all types of quantum or classical waves. Incorporating the vector nature of light leads to polarisation singularities, also geometrical, describing lines where the polarisation is purely circular or linear. With hindsight, it is clear that singular optics started in the 1830s. The levels form a hierarchy, leading to predictions of phenomena at the quantum level.

References

1. Berry, M.V. “The singularities of light: intensity, phase, polarisation,” Light, Science and Applications, Vol. 12, 1-4, 2023.

About the speaker: Sir Michael Berry is a mathematical physicist known for his research in the ‘borderlands’ between classical and quantum theories and ray and wave optics. His emphasis is on geometrical singularities such as ray caustics and wave vortices. Michael discovered the geometric phase, a phase difference arising from cyclically changing conditions with applications in many areas of wave physics, including polarisation optics and condensed matter.

Michael has received numerous awards, including the London Mathematical Society’s Pólya Prize, the Institute of Physics Newton Medal (2025), Maxwell Medal and Dirac Medal, the Royal Society’s Royal Medal, the Wolf Prize and the Lorentz Medal.

Refreshments will be provided beforehand. Please register your interest via Registration for SoMS "Waves and PDEs" Colloquium – Fill out form