基于二值振幅调控的角向偏振光超振荡聚焦平面透镜

角向偏振聚焦光场在超分辨光学显微、粒子操控等领域有着重要的应用。为克服传统透镜体积大、不利于集成等不足，本文提出了一种基于二值振幅(0，1)调控的角向偏振光超振荡聚焦平面透镜。针对波长λ=632.8 nm，设计、制备了超振荡平面透镜样品。透镜半径为650λ，焦距为200λ，数值孔径NA=0.96。实验结果表明：聚焦光场在焦平面上形成的空心聚焦光场呈圆环结构；空心环内径半高全宽为0.368λ，小于超振荡判据(0.38λ/NA=0.398λ)；最大旁瓣比为36.7%。该平面透镜具有结构尺寸小、厚度薄、便于加工等优点，可用于光学系统的微型化和集成化。

Binary-amplitude modulation based super-oscillatory focusing planar lens for azimuthally polarized wave

Tight focus of azimuthally polarized wave finds its applications in optical super-resolution, particle trapping and so on. To overcome the disadvantages of conventional optics, including bulky size and difficult for integration, a binary-amplitude (0, 1) super-oscillatory planar lens is designed for sub-diffraction focusing of azimuthally polarized wave at wavelength of 632.8 nm. The lens radius is 650λ, and its focal length is 200λ. The corresponding numerical aperture is 0.96. The experimental results demonstrate the generation of a hollow spot with circular ring shape on the focal plane. The inner full-width-at-half-maximum of the hollow spot is 0.368λ, smaller than the super-oscillatory criterion (0.398λ), and the maximum sidelobe ratio is about 36.7%. Such planar lenses are easy to fabricate. Their small size and ultra-thin thickness make them promising in system minimization and integration for different applications, such as optical microscopy, optical trapping and ultra-high density data storage.