Research and application of femtosecond laser processing of SERS substrate structure

Surface Enhanced Raman Spectroscopy (SERS) is a powerful analytical tool capable of highly sensitive detection of nanoscale molecules. Femtosecond laser processing offers a versatile method for fabricating SERS substrates with the advantages of minimal heat affected zone, high resolution and good control. This review describes the main femtosecond laser strategies used to fabricate SERS substrates, categorizing the methods into top-down techniques (e.g. laser-induced periodic surface structuring (LIPSS) and femtosecond laser spatial shaping techniques, etc.) and bottom-up methods (including femtosecond laser sintering and femtosecond laser-induced forward transfer, etc.). We also analyze recent advances in femtosecond laser fabricated SERS substrates for a variety of applications, including trace chemical detection, food safety assessment, and biomedical diagnostics. These advances highlight the promise of femtosecond laser processing for SERS substrate innovation, and identify areas for future research to expand the application potential.