Year: 2025
Type: article
Abstract: Owing to the ubiquity and easy-to-shape property of optical intensity, the intensity gradient force of light has been most spectacularly exploited in optical manipulation. Manifesting the intensity gradient as an optical torque to spin particles is of great fascination on both fundamental and practical sides but remains elusive. Here, we theoretically predict the existence of the optical intensity-gradient torque in the interaction of light with chiral particles. Such a new type of torque derives from the interplay between chirality-induced multipoles, which switches its direction for particles with opposite chirality. We show that this torque can be directly detected by a simple standing wave field, created with the interference of two counterpropagating plane-like waves. Our work offers a unique route to achieve rotational control of matter by tailoring the field intensity of Maxwell waves, demonstrated through three-dimensional spinning of a trapped chiral particle. It also establishes a framework that maps a remarkable connection between the optical forces and torques, across chiral to non-chiral.
Source: Photonics Research
DOI: 10.1364/prj.566257
Authors: Jiquan Wen, Huajin Chen, Hongxia Zheng, Shaohui Yan, Baoli Yao, Olivier J. F. Martin, Xiaohao Xu, Zhifang Lin
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4412477221