通过拉盖尔-高斯(LG)模式光束的等权重线性叠加, 制备了焦斑形貌为双螺旋的光束。选择模式面内斜率为3的直线上的5个模式进行叠加, 增加了双螺旋焦斑的螺旋圈数,增强了手性并增加了谱宽, 但是同时旁瓣光较强, 双光子聚合过程中双螺旋的两个主瓣会发生粘连。提出的紧聚焦下的双高斯函数和阶跃函数相结合的优化方法, 可明显抑制旁瓣光并制备出纯相位板。将符合要求的纯相位板加载到空间光调制器中, 通过单次曝光聚合, 最终得到了高螺旋圈数且无粘连的双螺旋微结构。

Beams with double-helix shaped focal spots are obtained by equally weighted linear superposition of Laguerre-Gauss(LG)beams. Five modes along the line with a slope of 3 in the modal plane are chosen for superposition, which increases the number of spirals in the double-helix focal spot, enhances the chirality, and broadens spectral bandwidth. However, side lobes simultaneously enhance, which results in severe adhesion of two main lobes during the process of two-photon polymerization. One optimization algorithm with the combination of double-Gaussian function and step function under the tight focusing condition is proposed here which can obviously suppress the side lobes and realize a phase-only mask. This phase-only mask is loaded on the spatial light modulator and a double-helix microstructure with both non-adhesion and more spirals is finally fabricated with a single exposure.