6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
**Tours now open!** Registration is now closed - All registration payments are due before 23:39 SAST on 26 June.

Space-time light sculpturing by bound states in the continuum

8 Jul 2026, 16:20
1h 20m
Great Hall ( University of the Western Cape)

Great Hall

University of the Western Cape

Oral Presentation Track A - Physics of Condensed Matter and Materials Poster Session 2

Speaker

Kelsey Everts (University of the Witwatersrand)

Description

Recent nanotechnology and metasurface advancements have enabled ultraprecise light control, catalysing developments in energy conversion, sensing and imaging. Simultaneously, structuring light in space-time has opened new realms for exploring the physics of both fundamental and applied light-matter interactions. Unfortunately, conventional space-time light structuring methods require large, complex optical setups presenting a formidable challenge for widespread usage. Here we experimentally demonstrate a novel simple single-step metasurface design for creating high-fidelity optical vortices in space-time addressing these challenges by exploiting the extraordinary compactness and stability of metasurfaces. Our design employs two offset subwavelength PTFE and copper gratings. This forms a 2π spiral phase by breaking mirror symmetry at the Γ-point and utilizing the structure’s quasi-bound state in the continuum (q-BIC) mode. We showcase this device’s versatility by generating space-time scalar beams, vector beams and even skyrmions, in all cases showing excellent agreement between our numerical simulations and experiments. This work thus achieves single-step, compact sculpturing of light in both space and time, paving the way toward more widespread usage of spatiotemporal light with subwavelength engineered metasurfaces.

Apply for student award at which level: PhD
Consent on use of personal information: Abstract Submission Yes, I ACCEPT

Author

Kelsey Everts (University of the Witwatersrand)

Co-authors

ANDREW FORBES (U. Witwatersrand) Renwei Zou (College of Optical Science and Engineering, Zhejiang University) Yungui Ma (Zhejiang University, Hangzhou, China)

Presentation materials

There are no materials yet.