多孔硅表面缺陷光子晶体的传感模型及特性

Sensing Model and Performance of the Surface Defect Photonic Crystal with Porous Silicon

提出了多孔硅表面缺陷光子晶体结构,引入多孔硅敏感层及吸收介质层形成表面缺陷腔,利用多孔硅高效的承载机制,将其作为待测样本的传感区域;由于吸收介质Zn S对谐振波长的吸收,可在反射光谱中获得与谐振波长对应的缺陷峰。以多孔硅的厚度为被优化变量,利用反向传播神经网络进行结构参数优化获得多孔硅的厚度最优值。由Goos-H?nchen位移建立待测样本浓度与缺陷峰波长的关系模型,进而对该结构进行传感特性分析。结果表明,优化结构参数后,缺陷峰对应的反射率由31.23%下降到0.00129%,其Q值可达1537.37。在传感特性研究中,每1%质量分数的灵敏度为2.5 nm。该表面缺陷光子晶体传感结构可为样本浓度、组分等信息的监测提供一定的理论参考。

The photonic crystal structure containing surface defect with porous silicon is proposed, in which the defect cavity on the surface is established by introducing the porous silicon layer and the absorbing medium layer, and the sensing region of the sample detected is formed by the use of the efficient carrying mechanism of the porous silicon. Because of the absorption of Zn S, the light corresponding to the resonant wavelength is absorbed and the defect peak is obtained in the reflection spectrum. The back propagation neural network is adopted to optimize the thickness of porous silicon globally. The relationship model between the concentration of the sample detected and the defect peak wavelength is established according to the GoosH？nchen shift and the sensing performance is analyzed. The simulation results show that the reflectivity of the defect peak decreases from 31.23% to 0.00129% and the Q value can attain to 1537.37 after the optimal design of structural parameter. The sensitivity of the sensor structure is about 2.5 nm at per 1% mass fraction, which can provide effective theory guidance for the detection of the concentration and composition of samples.