在偏振控制光强调制型SPRi传感器中,使用真实液体消光的方法实验调节困难,测量灵敏度低,线性度差.为此,提出无需真实液体消光,并将消光折射率左移的方法.首先,对在测量起点(即纯水)消光的传统方法进行光学参数的最优值仿真及其加工和调节误差仿真,结果表明,误差会引起SPRi曲线最低点在折射率轴上的左右偏移,从而影响传感器性能.接着,将消光折射率左移至1.325处,并仿真其光学参数的最优值.实验表明,与前者相比,1.325消光方法中存在的误差不会使测量曲线出现非单调的情况,此时的测量灵敏度高,线性度好,折射率分辨率达到1.85×10-6 RIU,对应NaCl溶液的检出限为35 mg/L.上述方法提高了误差存在时SPRi传感器的适用性,可以实现微量水溶液样品的高灵敏及高通量检测.%Light extinction method with real liquid is difficult to be realized in the experiment of the polarization controlled light intensity modulated SPRi sensor.Meanwhile,the sensor bearslow sensitivity and poor linearity.Therefore,the extinction method of shifting extinction refraction index forward without real liquid is proposed.First,the simulations on optimal optical parameters and their errorsarising from machining and adjustment were carried out through the former method whose extinction refractive indexis locatedat the starting point(pure water)of the measurement curve.It''s indicated that the errors will cause the shifts of SPRi curve''s lowest pointon the refractive index axis.Consequently the performance of the sensor will be influenced.Then,the extinction refractive index was shifted to 1.325,and the optimal values of the parameters were simulated.The experimental results show that compared with the former method,the errors in 1.325 extinction method do not make the measurement curve non-monotonic,and high sensitivity,good linearity are obtained.The refractive index resolution is 1.85×10-6 RIU and the corresponding detection limit of NaCl solution is 35 mg/L.The proposed method improves the applicability of SPRi sensor with the existence of errors,and highly sensitive and throughput detection of trace amounts of samples in aqueous solutions can be achieved.
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