Research On SPR-Like Optical Fiber Sensing Technology Based On Dielectric Nanoparticles

Micro/nanofiber has many advantages,such as ultra-low coupling loss,smooth waveguide surface,uniform external diameter,high bound optical evanescent field,high mechanical flexibility and very light mass.These characteristics make micro/nano fiber has the great application value in basic research of fiber optics,near-field optics,nonlinear optics and quantum optics,as well as in micro/nano scale optical transmission,coupling,modulation,resonance,amplification and sensing devices.In this thesis,micro/nanofiber and nanoparticles are combined.The optical properties of local light field enhancement effect of dielectric nanoparticles and local light field enhancement effect of metal nanoparticles has been compared through simulations and experiments.The sensing performance of micro/nanofiber modified with different nanoparticles was studied;the influence of different parameters and different concentrations of nanoparticles on the sensing performance of micro/nanofiber are explored.At the same time,the temperature was measured by using the micro/nanofiber elaborated by silicon nanoparticles.The main content of this thesis is as follows:(1)The simulation models of micro/nanofiber filled with silver nanoparticles and silicon nanoparticles,the film-coated micro/nanofiber have been established.The spectral characteristics and refractive index sensing sensitivity were analyzed by theoretical simulation,and the optical properties were tested by experiments.(2)The optical properties and refractive index sensing properties of micro/nanofiber coated with nanoparticles were studied.Silver nanoparticles and silicon nanoparticles were physically coated on at around 3μm diameter micro/nanofiber cones,respectively.Their sensing properties were studied.The silver nanoparticles probe has been experimentally demonstrated with a refractive index sensitivity of 13.05dB/RIU and the silicon nanoparticle probe has the refractive index sensitivity of 9.96dB/RIU.(3)The influence of different parameters on the sensing performance of micro/nanofiber was studied.The parameters include the period of spectrum,the length of sensing region,the type and concentration of coated nanoparticles.The sensitivity of the same parameters of the micro/nanofiber before and after nanoparticles-coating have been compared.The sensing performance of the micro/nanofiber coated with different concentrations of silicon nanoparticles and silver nanoparticles were compared and analyzed.Furthermore,the sensitivity of the micro/nanofiber has been effectively improved,the increased number is about 650nm/RIU.(4)High sensitivity temperature measurement was realized by using micro/nanofiber coated with the silicon nanoparticles in the range of 28℃ to 43℃.The silicon nanoparticles elaborated micro/nanofiber was encapsulated into a capillary glass tube filled with glycerol aqueous solution,whose refractive index will change depending on the temperature,thus affects the characteristics of the spectrum to determine the environmental temperature.The corresponding temperature sensitivity was determined to be 2.08nm/℃ with R2=0.98556.