Fiber SERS Probes Fabricated With Laser-induced Method And Their Applications

Surface enhanced Raman scattering spectroscopy is characterized by"fingerprint",high sensitivity and nondestructive testing,which gives it great potential in environmental science,biomedical science and food safety.By combining fiber sensing technology with SERS effect,fiber probes show good advantages of large area of interaction between light and molecules.Compared with traditional planar SERS substrate,the whole SERS-active area could contribute to generating and collecting the SERS signal,which makes fiber probe a promising candidate for high sensitivity and good repeatability in SERS detection.In particular,optical fiber probes have received great attention from biomedicine and process monitoring field in term of in-vivo,on-line and in-situ detection.Considering the practical demand of fiber SERS probes,in this thesis,we work on developing laser-induce method to realize the controllable,repetitive and batch preparation of optical fiber SERS probes.So far,we have preliminarily applied these optical fiber probes to pesticide residues,polychlorinated biphenyls and antibiotics detection.Surface enhanced Raman scattering spectrum and commonly used substrates are outlined,the fabrication status of fiber probes are emphatically analyzed.Besides,the theoretical research of optical fiber SERS probe is introduced in this thesis.Flat fiber SERS probes are fabricated with the method for laser-induced self-assembly method in a meniscus.We study the influences of fiber position,induced laser power and induced laser time on the performance of fiber SERS probes.Flat fiber SERS probes prepared under optimized conditions show good repeatability and detection sensitivity for carbamate pesticide thiram and organophosphorus pesticide methyl parathion are 10-7M and 5×10-7M respectively.Laser-induced dipping-lifting method is developed to prepare high performance tapered fiber SERS probes by optimizing lifting speed,induced laser power and laser drying time.Tapered fiber SERS probes show good repeatability and the detection limit of thiram,PCB77 and PCB3 could reach 10-9M,10-7M and 10-7M respectively.In addition,tapered fiber probes are used to indentify tetracycline in milk and components of tea.These work may laid a foundation for practical samples.