Opt Lett. 2023 Feb 15;48(4):920-923. doi: 10.1364/OL.476691.
Optical beams with a pure longitudinally polarized field are of great interest for their unique properties and promising applications in various fields such as optical trapping and three-dimensional microscopy. Here, an all-dielectric metasurface is proposed to directly generate Bessel beams with tunable longitudinally polarized electric and magnetic fields under a simple incidence of linear polarization. Under the incidence of horizontal polarization, a Bessel beam with a pure longitudinally polarized electric field can be generated, which can be turned to a beam with a pure longitudinally polarized magnetic field when the incidence is switched to vertical polarization. More importantly, it is further demonstrated that the longitudinal components of the electric and magnetic fields can be accurately manipulated between zero and the maximum by simply changing the polarization angle of incident light. The simplicity and flexibility of this proposed metasurface may provide new possibilities in ultracompact photonic devices for optical trapping, optical storage, and related fields.
具有纯纵向偏振场的光束因其独特的性质和在光学捕获和三维显微镜等各个领域的广阔应用前景而备受关注。本文提出了一种全介质超表面，可在简单的线性偏振入射下直接产生具有可调谐纵向偏振电场和磁场的贝塞尔光束。在水平偏振入射下，可产生具有纯纵向偏振电场的贝塞尔光束，当入射光切换为垂直偏振时，可将其转换为具有纯纵向偏振磁场的光束。更重要的是，进一步证明通过简单地改变入射光的偏振角，可在零到最大值之间精确地操纵电场和磁场的纵向分量。这种所提出的超表面的简单性和灵活性可能为用于光学捕获、光存储和相关领域的超紧凑光子器件提供新的可能性。
