Center of Ultra-precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin, China.
Opt Lett. 2013 Aug 1;38(15):2742-5. doi: 10.1364/OL.38.002742.
A high NA Fresnel zone plate (FZP) is studied using vectorial angular spectrum theory for realizing the sharpest possible super-Gaussian optical needle with purely longitudinal polarization illuminated by a radially polarized vector beam. Strong dispersion of the FZP results in a light field resembling a super-Gaussian optical needle by selecting an optimal FZP structural wavelength relative to the illumination wavelength and inserting a narrow comb window function into the center-shaded FZP. A 25 μm long longitudinally polarized flattop optical needle with a transverse beam width of about 0.366λ is focused at a distance of 222.5 μm away from a binary amplitude 3.46 mm diameter FZP for a 532.4 nm wavelength in free space.
采用矢量角谱理论研究了高 NA 菲涅耳波带片（FZP），以实现通过径向偏振矢量光束纯纵向偏振照明的最尖锐的超高斯光学针。通过相对于照明波长选择最佳的 FZP 结构波长并在中心阴影 FZP 中插入窄梳状窗口函数，FZP 会产生强烈的色散，从而产生类似于超高斯光学针的光场。对于自由空间中的 532.4nm 波长，对于二进制幅度为 3.46mm 直径的 FZP，在 222.5μm 的距离处聚焦具有约 0.366λ 的横向光束宽度的 25μm 长的纵向偏振平顶光学针。
