Hybrid Femtosecond Laser 3D Processing Technology for Rapid Integration of Functional Optical Devices on Fibers

Abstract

Due to constraints imposed by the geometry characteristics of optical fibers and conventional preparation strategies, the development of “Lab on Tip” devices faces significant challenges. By introducing two-photon polymerization (TPP) technology, it becomes feasible to develop arbitrarily complex 3D structures with nanoscale features on fiber tips. However, the serial scanning process of TPP is too slow to accommodate the extensive application expansion of fiber tip devices. Herein, a hybrid femtosecond laser 3D processing technology (termed “FPL-DLW”), developed by combining femtosecond projection lithography (FPL) with direct laser writing (DLW), is reported. FPL is adopted to print bulk base structures and DLW is employed for precision realization of functional nanostructures. Using a common polarizing beam splitter as a bridge, the two independent optical systems with different polarized light sources are facilely integrated to realize hybrid processing. The FPL-DLW utilizes FPL (high-efficiency) and DLW (high-precision) to flexibly fabricate multiple types of fiber tip functional devices, whose processing efficiency can be boosted by up to two orders of magnitude compared to using DLW alone. These results validate that the authors’ method provides a universal solution for the rapid integration of micro–nanostructures on various fiber end facets, which is challenging with existing TPP technologies.