Metal Surface-enhanced Raman Scattering Substrate Fabricated By Femtosecond Laser Based On Electron Dynamic Control

Surface enhanced Raman scattering(SERS)can be applied to the analysis of molecular structure information quickly and accurately,which is of great significance for the detection of low concentration substances.Femtosecond laser processing technology is one of the ideal methods to fabricate surface-enhanced Raman substrate with its ultra-fast and super-power characteristics.Through the idea of electronic dynamic control proposed by our group,we used femtosecond laser to process the metal materials.By continuously optimizing the experimental parameters,the surface-enhanced Raman substrates with high sensitivity and uniformity were prepared in one step under air condition.The main research work and innovation are summarized as follows:(1)Fabrication of silver substrate by femtosecond laser pulse and pulse delay.We use the femtosecond laser pulse delay to process the silver substrate and obtain the Surface-enhanced Raman substrate with high sensitivity in one step in air.It has the following advantages:High sensitivity:the maximum SERS enhancement factor is 1.26×109.High efficiency:the fabrication rate can be up to 96,000 ?m2 per minute,which is 20-40 times faster than femtosecond photochemical reduction.Good reproducibility:the relative standard deviation of the Raman signal intensity is 10.7%,which is one third of that for conventional femtosecond laser;Eco-friendly fabrication:neither chemical reagents nor vacuum conditions are needed during the fabrication process.(2)Fabrication of surface-enhanced Raman substrates by femtosecond laser pulse machining of copper substrate.The femtosecond laser is used to ablate the copper directly.By changing the processing speed of the femtosecond laser,the copper with superhydrophobic characteristics is obtained.By adjusting the processing speed of the femtosecond laser,the hydrophobic angle of the copper surface can be controlled.Using the superhydrophobic characteristics of the substrate to be detected droplets concentrated to a very small surface area for Raman detection the EF of which can be a 1.91 ×107.(3)Processed Cu with self-assembly gold nanoparticles.On the basis of the research content(2),60nm gold nanoparticles are modified by self-assembly technique to obtain the enhancement factor of 3.60 ×109.At the same time,in order to verify the effect of gold nanoparticles,the microstructure of copper and gold nanoparticles are simulated by FDTD simulation.The results showed that the combination of Au nanoparticles and Cu nanostructures could improve the surface electromagnetic field enhancement,which is the reason of the enhanced Raman scattering effect.