Li Hongliang, Wen Jisen, Gao Song, Choi Duk-Yong, Kim Jin Tae, Lee Sang-Shin
Department of Electronic Engineering, Kwangwoon University, Seoul, 01897, South Korea.
Nano Device Application Center, Kwangwoon University, Seoul, 01897, South Korea.
Nanoscale. 2023 Nov 9;15(43):17364-17372. doi: 10.1039/d3nr04125e.
Optical trapping is a state-of-the-art methodology that plays an integral role in manipulating and investigating microscopic objects but faces formidable challenges in multiparticle trapping, flexible manipulation, and high-integration applications. In this study, we propose and demonstrate a switchable optical scheme for trapping microparticles incorporating disparate vortex-pair beams generated by a polarization-multiplexed metasurface. The miniaturized all-dielectric metasurface, which comprises an array of titanium dioxide nanoposts, was manufactured and characterized to provide polarization-tuned two-fold vortex-pair beams. The profiles of the created vortices can be flexibly tailored by adjusting the combination of topological charges and the separation among phase singularities. Under transverse electric polarized light conditions, a vortex-pair beam with opposite topological charge combinations traps a single microparticle within one beam spot, while under transverse magnetic polarization conditions, two microparticles are captured simultaneously by a vortex-pair beam with the same topological charge signs. The proposed switchable trapping scheme (incorporating a vortex-pair light beam) is expected to feature enhanced integration and flexible manipulation of multiple particles with potential applications in biophysics, nanotechnology, and photonics.
光镊是一种先进的方法，在操纵和研究微观物体方面发挥着不可或缺的作用，但在多粒子捕获、灵活操纵和高集成应用方面面临巨大挑战。在本研究中，我们提出并演示了一种用于捕获微粒子的可切换光学方案，该方案结合了由偏振复用超表面产生的不同涡旋对光束。制造并表征了由二氧化钛纳米柱阵列组成的小型全介质超表面，以提供偏振调谐的双涡旋对光束。通过调整拓扑电荷的组合和相位奇点之间的间距，可以灵活地定制所产生涡旋的轮廓。在横向电极化光条件下，具有相反拓扑电荷组合的涡旋对光束在一个光斑内捕获单个微粒子，而在横向磁极化条件下，具有相同拓扑电荷符号的涡旋对光束同时捕获两个微粒子。所提出的可切换捕获方案（结合涡旋对光束）有望实现增强的集成和对多个粒子的灵活操纵，在生物物理学、纳米技术和光子学等领域具有潜在应用。
