On-Fiber 3D Nanoprinted Antiresonant Hollow-Core Waveguides for Integrated Optofluidics

Guiding light in hollow cores represents a major research direction in modern fiber optics, enabling numerous transformative applications. However, structural and fabrication constraints have hindered the implementation of such waveguides in planar platforms, limiting their wide-range application. In this study, we present a new class of high-quality, fiber-integrated hollowcore waveguide that directly adapt the antiresonant guiding mechanism from fiber technology to planar waveguide technology using 3D nanoprinting. By directly fabricating record-high aspect ratio waveguides on fiber end faces, a seamless photonic integration with enhanced optical performance, including polarization-independent transmission and substantially reduced losses is achieved. The approach is supported by strong agreement between experimental results, numerical simulations, and analytical modeling. The relevance of the fiber-inspired platform in the context of optofluidics has been demonstrated by high-precision refractive index sensing and dye-related absorption spectroscopy. These results highlight the potential of the approach to serve as a compact, versatile platform for advanced fiber-based systems in biomedicine, quantum optics, and environmental monitoring.