Optical Fiber Tweezers Based on End-Face Micro-Nanostructures

Optical fiber tweezers enable the transmission of light over extended distances to trap micro- and nano-objects, offering the advantages of a compact design, flexible operation, and easy integration with endoscopic systems. These attributes have gained significant attention for manipulating and analyzing biological samples. Compared to traditional flat-cleaved optical fibers, micro-nanoscale structures on the fiber end-face allow for enhanced control over the emitted wavefront, focal field, and optical forces, thereby facilitating stable three-dimensional trapping, dynamic modulation, and signal analysis of samples. Recent advancements in micro-nano fabrication techniques have transformed the fiber end-face from a simple light-emitting interface into a sophisticated miniature multifunctional platform, which integrates capabilities such as focusing, near-field enhancement, multi-potential well creation, transmission mode regulation, and signal detection. This paper provides a review of recent progress in optical fiber tweezers based on various fiber end-face structures, introduces their structural characteristics and applications in particle manipulation, biological analysis, and microfluidic systems, and offers perspectives on future developments.