Research On Localized Surface Plasmon Resonance Refractive Index Sensor Based On Photonic Crystal Fiber

In this paper,the localized surface plasmon resonance(LSPR)refractive index sensor based on D-shaped photonic crystal fiber(PCF)is studied.The sensor performance is improved from the light guiding mechanism of photonic crystal fiber and the principle of localized surface plasmon resonance.The sensor structure is modeled and simulated by finite element method,and the influence of various structural parameters on the sensing performance is studied.The main research results of this paper are as follows:1.A high-sensitivity D-shaped PCF-LSPR sensor for low refractive index liquid sensing is designed.When all structural parameters are optimal,the change trend of the resonant wavelength when the refractive index of the analyte changes is simulated,and calculate the sensitivity of the sensor.Finally,the maximum sensitivity of the sensor is16400nm/RIU,and the detectable refractive index range is 1.26-1.33.2.On the basis of Scheme 1,the air hole structure is optimized,and a D-shaped PCF-LSPR sensor that can achieve double measurement is designed.The sensor uses four different size air holes,and introduces a central air hole in the fiber core,reducing the effective mode field area of the fiber core,so that more energy can be transmitted to the plasma material area.The simulation results show that when the refractive index of the analyte is 1.38 and 1.39,the sensor has two resonant peaks in different wavebands.The resonant wavelength at the short wavelength has a red shift,while the resonant wavelength at the long wavelength has a blue shift.Therefore,the sensor can achieve double precision measurement in two wavebands,and can achieve wide range detection of 1.33-1.40 at the short wavelength.Its maximum sensitivity is 15500nm/RIU.At long wavelength,the sensor can realize accurate measurement of analytes with refractive index of 1.38-1.39,and its maximum sensitivity is 25000 nm/RIU.3.Based on the first two schemes,a PCF-based near-infrared short-wavelength LSPR refractive index sensor is designed,and the core part of the sensor has four atmospheric holes to confine light propagation in the core;The simulation results show that the measurement range of the sensor is 1.35-1.41,the maximum sensitivity is11600nm/RIU,and the resonance wavelengths are all in the short wavelength range of near-infrared,about 920nm-1320 nm.The LSPR sensor that can achieve high sensitivity in the short wavelength of near-infrared is realized.