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 optica...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.展开更多
基金National Natural Science Foundation of China(12174076,12204117,12274181)National Key Research and Development Program of China(2023YFF0613700)+1 种基金Guangxi Science and Technology Project(2023GXNSFFA026002,2024GXNSFBA010261,2021GXNSFDA196001,AD23026117)Open Project of State Key Laboratory of Surface Physics at Fudan University(KF2022_15).
文摘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.
