Structured Light Reveals New Insights Into Radiation Pressure

Researchers from the Centre of Light for life have published a new article titled “Radiation pressure revisited: historical context and the role of structured light,” in the Journal of Optics.

The authors are Alexander C Trowbridge, Ewan M Wright and Kishan Dholakia.

Light is known to carry momentum, and when it reflects from a surface, it exerts a tiny push known as radiation pressure. While this phenomenon has typically been studied using simple, uniform light beams, advances in optics now allow scientists to create “structured light” with complex twists and patterns.

In this new study, the authors review the history of radiation pressure and explore how it changes when moving from simple beams to structured light. When light is shaped into beams with twists or patterns, the pressure it exerts is slightly weaker than that of a simple beam of the same brightness. For certain types of patterned light, the difference is miniscule - about 20 femtonewtons (a quadrillionth of a newton) for each unit of twist - but still within the reach of today’s most sensitive measuring tools.

The team also outlines a feasible experimental approach (pictured) to detect this effect with current measurement techniques. These findings deepen our understanding of how light interacts with matter and point toward new opportunities for precision optical experiments.

Read the paper here: https://iopscience.iop.org/article/10.1088/2040-8986/ade8fb