Surface Enhanced CARS Study Of Ag-SiO₂ Double Layer Structure

Since the discovery of Raman scattering,it has been widely used in various subject areas.In this paper,Raman spectroscopy and Coherent anti-Stokes Raman scattering(CARS)are the main research contents,and the following three aspects are worked:First of all,this paper comprehensively discusses the development history,basic principles and applications of Raman spectroscopy and surface enhanced Raman spectroscopy and CARS.Then,the surface-enhanced Raman effect and CARS are combined to propose a simple and convenient method for fabricating the reinforcing substrate.The composite substrate synthesized by this method can effectively improve the intensity of the CARS signal.Specifically,the ethanol dispersed silica microsphere solution was uniformly dispersed on the glass substrate by using a homomixer;then the silver film was sputtered by magnetron sputtering.The enhancement effect of the substrate was characterized by Rhodamine 6G(R6G).The results show that the substrate not only has good Raman enhancement properties,but also has good stability and uniformity.Coherent anti-Stokes Raman spectroscopy is a rapidly developing detection method in recent years.Measuring the coherent anti-Stokes Raman spectroscopy of R6 G on this substrate also has good enhancement characteristics.Finally,since most plants themselves have strong fluorescent properties,few can be observed using Raman spectroscopy.We used the CARS ultrafast spectral imaging system to achieve two-dimensional and three-dimensional spatial distribution imaging of ?-carotene in carrots.The study found that ?-carotene is mainly distributed between the interstitial cells,and the concentration varies with the position of the carrot.This provides a new technical approach to study the distribution of ?-carotene in plants.