Research On The Photonic-crystal-fiber-based Sensor Filled With Nano-composite Materials

The design flexibility and excellent optical characteristics of photonic crystal fiber?PCF?make it stand out in both scientific research and applications of fiber sensing technology.Especially,the PCF sensors based on surface plasmon resonance?SPR?gradually become the focus of current research in biomedical detection,chemical sensing,environment protection and food safety because of their outstanding properties such as high sensibility,low sample demand and real-time detection.In this thesis,we designed three kinds of PCF-SPR sensors by filling nano-composite materials into PCFs and numerically simulated their sensing properties by using finite-elements-method-based software.The main contents and innovation points of this thesis are summarized as follows:?1?The properties and applications of PCF,the principle and development of SPR,as well as the concept and current status of nano-composite materials are comprehensively introduced.Especially,the development process and recent research status of PCF-SPR sensors are demonstrated in detail.?2?The theoretical research methods of PCF-SPR sensors are comprehensively introduced,including the numerical research methods of PCF,the principle as well as the calculation methods of SPR sensing technology and the electromagnetic field theory of nano-composite materials.All of these provide the theoretical basis for the design of the sensors and the study of their sensing properties.?3?We designed a PCF-SPR sensor by filling Ag-Au nano-composite materials into PCF.The sensing properties of it have been numerically simulated and the structural parameters have been optimized.Compared with the PCF-SPR sensor filled with silver nano-materials,the spectral sensitivity,the amplitude sensitivity and the figure of merit of the proposed sensor are all promoted.Meanwhile,the existence of gold shell can protect the silver core from oxidation,which means high system stability and long lifetime.?4?We designed a PCF-SPR sensor by filling SiO₂-Au nano-composite materials into PCF and numerically simulated its sensing properties.The resonant wavelength of this PCF-SPR sensor was extended to the near-infrared region,which made PCF-SPR technology much more attractive in chemical and biological sensing.Furthermore,it was demonstrated that the resonant wavelength of the sensor can be precisely tuned in a broad range,660nm to 3.1?m,by varying the structural parameters of SiO₂-Au nano-composite materials.?5?We designed a PCF-SPR sensor filled with Au-SiO₂-Au multilayer nano-composite materials.The sensing properties of the sensor and the influence of the parameters on the sensing performance have been numerically simulated and systematically analyzed.It has been demonstrated that there exist two resonant loss peaks in the spectrum of the sensor,which provided the possibility to realize self-reference in the sensing process.Meanwhile,the resonant wavelength of the two peaks can be precisely tuned in visible and near-infrared regions,respectively,by varying the structural parameters of Au-SiO₂-Au multilayer nano-composite materials.