Femtosecond picosecond laser fabricated nanostructures SERS based sensing applications

Abstract

1. Abstract: newlineThis thesis presents investigations on the surface-enhanced Raman scattering (SERS) performance of various types of nanostructures, including Hybrid NSs (a) made of metal NSs grafting anisotropic plasmonic NPs such as Au nanostars and (b) single-step fabrication of metal-semiconductor (Ge-Ag, Ge-Au) interfaces established with femtosecond laser structured with plasmonic nonentities substrates and fs laser fabricated germanium nanostructures (GeNSs) in conjunction with an Au film. The research also includes paper-based substrates loaded with colloidal [alloy Ag-Au (Ag, Ag70Au30, Ag50Au50, Ag30Au70, and Au NPs) plasmonic nanoparticles loaded in filter paper], with the intent of detecting common explosives, dye molecules as well as the use of a portable and micro-Raman spectrometer. The Ag-Au alloy nanoparticles are fabricated through picosecond (ps) laser ablation using the liquids approach. The chapter begins with a concise overview of high-energy compounds, including explosives, which belong to a specific category of these materials. It also discusses some detection methods that are now being used and have been recently generated. This work discusses Raman spectroscopy principles, SERS, the processes participating in Raman signal growth, and the optimal criteria of a SERS substrate. Furthermore, several distinctive manufacturing approaches for SERS substrates are addressed, including the perspective of the technique of laser ablation in liquid (LAL). In addition, the processes involved in the LAL Procedure for producing nanoparticles (NPs) and nanostructures (NSs) are also explored. Therefore, this chapter succinctly examines the theoretical foundation of the SERS method and its benefits in the sensitive identification of hazardous compounds and explosives. Furthermore, it describes the source of electromagnetic amplification in the SERS, the development of the enhancement factor, and the many techniques for producing SERS substrates. There is also an investigation of the differences (both benefits