We present a method to fabricate Fresnel zone plate (FZP) on the multimode fiber (MMF) tip by combining femtosecond laser direct writing with coating, polishing and chemical etching. After laser processing, the fiber tip coated by gold was polished to obtain a clear unprocessed region with high transmittance and a processed area filled with gold. By launching an 850 nm laser into the MMF, the light intensity distribution and coupling law of the fabricated FZP are studied. The experimental results indicate that the laser is focused at a distance of 900 μm out of the FZP.

中文翻译：

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飞秒激光在光纤尖端上制造的菲涅尔带中填充金

我们提出了一种结合飞秒激光直接写入与涂层，抛光和化学蚀刻的方法，在多模光纤（MMF）尖端上制造菲涅耳波带片（FZP）的方法。激光加工后，对涂有金的纤维尖端进行抛光，以获得具有高透射率的透明未加工区域和充满金的加工区域。通过将850 nm激光发射到MMF中，研究了制成的FZP的光强度分布和耦合规律。实验结果表明，激光聚焦在FZP之外900μm的距离处。