摘要
Optical tweezers have proved to be a powerful tool with a wide range of applications.The gradient force plays a vital role in the stable optical trapping of nano-objects.The scalar method is convenient and effective for analyzing the gradient force in traditional optical trapping.However,when the third-order nonlinear effect of the nano-object is stimulated,the scalar method cannot adequately present the optical response of the metal nanoparticle to the external optical field.Here,we propose a theoretical model to interpret the nonlinear gradient force using the vector method.By combining the optical Kerr effect,the polarizability vector of the metallic nanoparticle is derived.A quantitative analysis is obtained for the gradient force as well as for the optical potential well.The vector method yields better agreement with reported experimental observations.We suggest that this method could lead to a deeper understanding of the physics relevant to nonlinear optical trapping and binding phenomena.
作者
朱政
张聿全
闵长俊
Aurèle J.LAdam
H.Paul Urbach
袁小聪
Zheng Zhu;Yuquan Zhang;Changjun Min;Aurèle J.LAdam;H.Paul Urbach;Xiaocong Yuan(Research Center for Humanoid Sensing,Research Institute of Intelligent Sensing,Zhejiang Lab,Hangzhou 311100,China;Nanophotonics Research Center,Institute of Microscale Optoelectronics&State Key Laboratory of Radio Frequency Heterogeneous Integration,Shenzhen University,Shenzhen 518060,China;Optics Research Group,ImPhys Department,Faculty of Applied Sciences,Delft University of Technology,Delft 2628 CJ,The Netherlands)
基金
supported by the Key Research Project of Zhejiang Lab(No.2022MG0AC05)
the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030009)
the National Natural Science Foundation of China(Nos.61975128,61935013,and 62175157)
the Shenzhen Science and Technology Program(Nos.JCYJ20210324120403011 and RCJC20210609103232046)
the Natural Science Foundation of Guangdong Province(No.2019TQ05X750)
the Shenzhen Peacock Plan(No.KQTD20170330110444030)。
