Study On The Filtering And Sensing Application Based On One Dimensional Photonic Crystal

Photonic crystal?PC?is a new type of artificial material proposed in the1980s,it has rapidly become a new material with booming development and broad prospects because it shows special optical properties.In this paper,the time domain finite difference method?FDTD?is used to simulate and optimize the filtering of photonic crystals in different spectral bands.And the refractive index and solubility of sucrose solution were measured by PC sensing.The details are as follows:Firstly,a one-dimensional PC structure composed of Ag-ITO thin films was studied by FDTD method.In the range of 300nm-800nm,the effect of changing defect layer thickness,incident Angle and ITO film thickness on band pass filtering of PCs was calculated.The results show that the change of defect layer thickness can modulate the filtering performance of PC,but it is not affected by incident Angle,the filter spectrum changes periodically with the increase of ITO film thickness.Finally,the dispersion curves of photonic crystal structures with different parameters are calculated and the physical explanation of the phenomenon is given.Secondly,a one-dimensional PC model of?AB?^NC?AB?^N type is constructed.The transmission spectra of the one-dimensional PC are numerically simulated and analyzed by FDTD.The relationship between the PC transmission peak position and the refractive index of sucrose solution was obtained.The results show that there is a strict linear relationship between the concentration and refractive index of sucrose solution and the transmission peak of defect mode of PC,the position of transmission peak of PC moves in the direction of long wave with the increase of solution concentration percentage,and the solubility and refractive index of the solution were obtained by measuring the position of the defect mode transmission peak.According to the results,we put forward the solution for this kind of PC sensor solubility measurement sensitivity is as high as 498.087nm/RIU,which provides reference for the design of PC sensor and it is beneficial to the application of the solution concentration detection sensor.Finally,a one-dimensional composite photonic crystals was constructed,such as SiO₂/?Ag-SiO₂?^m/?Si-Al₂O₃?ⁿ.Results show that by adjusting the thickness of a photonic crystal film can make the 450nm to 780nm wavelength range of visible light efficiently through,200nm to 400nm range of uv shielding,at the same time can also be about 780nm to 1000nm range near-infrared light of inhibition.On the other hand,the study also found that the change of incident Angle under different polarization?TE/TM?modes had little effect on the ultraviolet filtering characteristics of the composite photonic crystal within the range of 0°-10°.