2023/05/26 by Karim Achouri, Mintae Chung, Achouri, Karim +5
Physics and Astronomy · #FOS: Physical sciences #Force Microscopy Techniques and Applications #Mechanical and Optical Resonators #Optics (physics.optics) #Orbital Angular Momentum in Optics
paper · pdf · doi:10.48550/arxiv.2305.16942
openalex publication_date 2023/05/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
It has been observed that achiral nano-particles, such as flat helices, may be subjected to an optical torque even when illuminated by normally incident linearly polarized light. However, the origin of this fascinating phenomenon has so far remained mostly unexplained. We therefore propose an exhaustive discussion that provides a clear and rigorous explanation for the existence of such a torque. Using multipolar theory, and taking into account nonlocal interactions, we find that this torque stems from multipolar pseudochiral responses that generate both spin and orbital angular momenta. We also show that the nature of these peculiar responses makes them particularly dependent on the asymmetry of the particles. By elucidating the origin of this type of torque, this work may prove instrumental for the design of high-performance nano-rotors.