Emerging frontiers in SERS-integrated optical waveguides: advancing portable and ultra-sensitive detection for trace liquid analysis

Surface-Enhanced Raman Scattering (SERS) integrated with optical waveguide sensing offers a transformative approach to overcoming the limitations of conventional SERS techniques, such as complex alignment requirements and limited signal collection efficiency. By leveraging the unique properties of optical waveguides, this integration significantly enhances detection sensitivity, simplifies sensor design, and enables the analysis of ultra-low concentration analytes in trace-volume samples. This review explores the latest advancements in combining diverse optical waveguide architectures with SERS technology, focusing on strategies to optimize the sensing interface and SERS substrate design for maximal Raman signal enhancement. By enabling efficient analyte excitation and enhanced scattered signal collection through waveguide-mediated light-matter interactions, this approach unlocks new possibilities for high-sensitivity Raman detection. Furthermore, we discuss the potential of this integration to drive breakthroughs in fields such as biomedical diagnostics, environmental monitoring, and chemical sensing, paving the way for next-generation, portable and ultra-sensitive sensing platforms.