Meet the Jury Simon Hanna on Swarms of optically controlled Janus particles

Arenberg Doctoral School is proud to invite you to Meet The Jury!

When internationally renowned experts visit KU Leuven as a member of a PhD Examination Committee, we like to seize this opportunity to give this expert a forum to a large audience. All members of Science, Engineering & Technology are most welcome to the Meet The Jury Lectures.

Dr. Simon Hanna (University of Bristol, UK) will give a lecture on “Swarms of optically controlled Janus particles”.

Optical Janus particles comprise two distinct parts that interact differently with a beam of light. The resulting asymmetry induces lateral forces that can be used to create a type of active particle swarm. There are many ways to create optical Janus particles. In the present case we consider two models: (1) we divide spheres into hemispheres with different refractive indices and (2) we glue together spheres of different refractive index. Illumination will induce a force and motion perpendicular to the interface between the two materials. Furthermore, optical binding will lead to clustering and ordering of the particles, which will give rise to further enhancements of the optical forces and, ultimately, the potential for swarming behaviour such as is observed in other active particles and natural systems including flocks of birds and shoals of fish. In this presentation I will describe the development of the optical and hydrodynamic model used to simulate swarms of such Janus particles and will show initial experimental results. At the end of the talk I will consider how closely this system comes to actually be considered a swarm.

Following the lecture, there will be opportunity for young researchers to interact with him.

• Venue: QDV 00.110, campus Arenberg III, KU Leuven (Celestijnenlaan 200 H, 3001 Leuven)
• Date: 7 October 2026 – 10:00-12:00
• Dr. Simon Hanna is visiting KU Leuven on the occasion of the PhD defence of Jui-Kai Chen