Femtosecond-laser nanomanufacturing of solid-state surface-enhanced Raman scattering substrates: Electromagnetic enhancement, chemical activation, and interfacial engineering

Surface-enhanced Raman scattering (SERS) spectroscopy has shown broad potential in chemical, biological, and environmental sensing owing to its ultrasensitive vibrational fingerprint recognition down to the single-molecule level. Compared with colloids, solid-state SERS substrates offer superior structural stability and fabrication reproducibility, facilitating on-chip integration. Unfortunately, the trade-off between fabrication efficiency and cost hampers their scalable production with homogeneous nanostructures. Femtosecond (fs) lasers combine ultrashort pulse durations for high-precision patterning and high peak powers for efficient processing, enabling the creation of multifunctional nanostructured surfaces through versatile optical-field manipulation. This review systematically summarizes advances in fs-laser nanomanufacturing of solid-state SERS substrates. According to the synergistic SERS mechanisms involving physical, chemical, and molecular enrichment processes, three main aspects are discussed: the construction of nanostructures, regulation of energy bands, and manipulation of solid–liquid interfaces. These are categorized into (i) fs-laser subtractive, formative, and additive manufacturing strategies for plasmonic nanostructures, (ii) fs-laser-induced defect engineering for energy band regulation and promotion of interfacial charge transfer, and (iii) fs-laser-modified surface wettability for enrichment of analyte molecules. Furthermore, the perspectives for high-throughput nanomanufacturing through optical field regulation using spatial light modulators and microlens arrays are discussed, holding promise for easily accessible, high-performance solid-state SERS substrates in the future practical applications.