Light beams with helical phase-fronts are attractive for many optical applications, such as optical tweezers, particle manipulation, and other optical applications. A superoscillatory metalens has been designed for an azimuthally polarized wave at a wavelength λ = 632.8 nm. Numerical simulation demonstrates that a superoscillation hollow dark spot is generated. The transverse inner FWHM is 0.358λ overcoming the diffraction limit, while the sidelobe ratio can be compressed to 18.3%. More importantly, for such incidence with different orbital angular momentum (OAM) l = 1, 2, and 3, the proposed metalens also presents elegant subwavelength tight focusing performances (the FWHMs are 0.469λ, 0.352λ, and 0.737λ, respectively). Extensive investigations have been made to present the unique characteristics of the generated foci, the phase distribution patterns are given for different OAM values. Small size and ultrathin thickness make such lenses suitable for various optical applications.

中文翻译：

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具有不同轨道角动量的方位极化波的超振荡超透镜

具有螺旋相前的光束对许多光学应用都很有吸引力，例如光镊、粒子操纵和其他光学应用。超振荡超透镜设计用于波长 λ = 632.8 nm 的方位极化波。数值模拟表明产生了超振荡空心暗点。横向内部 FWHM 为 0.358λ，克服了衍射极限，而旁瓣比可以压缩到 18.3%。更重要的是，对于这种具有不同轨道角动量 (OAM) l = 1、2 和 3 的入射，所提出的超透镜还呈现出优雅的亚波长紧密聚焦性能（FWHM 分别为 0.469λ、0.352λ 和 0.737λ）。已经进行了广泛的调查以呈现生成的焦点的独特特征，给出了不同 OAM 值的相位分布模式。小尺寸和超薄厚度使此类透镜适用于各种光学应用。