An inverse-designed metalens is proposed, designed, and fabricated on an optical fiber tip via a 3D direct laser-writing technique through two-photon polymerization. A computational inverse-design method based on an objective-first algorithm was used to design a thin circular grating-like structure to transform the parallel wavefront into a spherical wavefront at the near-infrared range. With a focal length about 8 μm at an operating wavelength of 980 nm and an optimized focal spot at the scale of 100 nm, our proposed metalens platform is suitable for two-photon direct laser lithography. We demonstrate the use of the fabricated metalens in a direct laser lithography system. The proposed platform, which combines the 3D printing technique and the computational inverse-design method, shows great promise for the fabrication and integration of multiscale and multiple photonic devices with complex functionalities.

中文翻译：

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用于激光直接光刻的光纤尖端上金属元素的逆向设计和3D打印

通过双光子聚合的3D直接激光写入技术，在光纤尖端上提出，设计和制造了逆设计的金属元素。利用基于目标优先算法的计算逆设计方法，设计了一种薄的圆形光栅状结构，将平行波前转换为近红外范围内的球面波前。我们提出的metalens平台具有在980 nm的工作波长下约8μm的焦距和在100 nm范围内的最佳焦点，适用于双光子直接激光光刻。我们演示了在直接激光光刻系统中使用制造的金属材料。所提出的平台结合了3D打印技术和计算逆设计方法，