Strong focusing on diffraction-limited spots is essential for many photonic applications and is particularly relevant for optical trapping; however, all currently used approaches fail to simultaneously provide flexible transportation of light, straightforward implementation, compatibility with waveguide circuitry, and strong focusing. Here, we demonstrate the design and 3D nanoprinting of an ultrahigh numerical aperture meta-fibre for highly flexible optical trapping. Taking into account the peculiarities of the fibre environment, we implemented an ultrathin meta-lens on the facet of a modified single-mode optical fibre via direct laser writing, leading to a diffraction-limited focal spot with a record-high numerical aperture of up to NA ≈ 0.9. The unique capabilities of this flexible, cost-effective, bio- and fibre-circuitry-compatible meta-fibre device were demonstrated by optically trapping microbeads and bacteria for the first time with only one single-mode fibre in combination with diffractive optics. Our study highlights the relevance of the unexplored but exciting field of meta-fibre optics to a multitude of fields, such as bioanalytics, quantum technology and life sciences.

对于许多光子应用，必须将焦点集中在衍射极限点上，这对于光陷波尤其重要。但是，当前所有使用的方法都无法同时提供灵活的光传输，简单的实现，与波导电路的兼容性以及强大的聚焦能力。在这里，我们演示了用于高度灵活的光学陷印的超高数值孔径超细纤维的设计和3D纳米打印。考虑到光纤环境的特殊性，我们通过直接激光写入在修改后的单模光纤的刻面上实现了超薄的变倍透镜，从而形成了衍射极限焦点，其光圈高达30％，达到了创纪录的高数值孔径。至NA≈0.9。这种灵活，经济高效的独特功能，通过仅用一根单模光纤与衍射光学器件光学捕获微珠和细菌，首次展示了生物和光纤电路兼容的超光纤设备。我们的研究突出了未开发但令人兴奋的超细纤维光学领域与生物分析，量子技术和生命科学等众多领域的相关性。