光子晶体对硝酸钠红外吸收特性的影响

制备了周期为10 μm、孔径7.8 μm左右的二维金属镍(Ni)光子晶体(正方形晶格)，并通过电镀方法增加Ni膜的厚度至约3 μm，考察了光子晶体的红外特性及其对水溶液中硝酸根(NO-₃)红外吸收特性的影响。实验结果表明，当光垂直入射光子晶体时，在1 450 cm-1附近出现透射峰，该透射峰正好处于水溶液中NO-₃的反对称伸缩振动频率范围(1 300~1 500 cm-1);经过光子晶体对红外光的调制，1 300~1 500 cm-1处的红外光透射率与NO-₃的反对称伸缩振动的红外吸收强度变化趋势基本一致，表明光子晶体对红外光强度的调制可以改变水溶液中NO-₃的红外吸收强度。

Effect of the Infrared Absorption Properties of Sodium Nitrate with Photonic Crystal

The two-dimensional photonic crystal (Ni mesh with square lattice of 10μm)was prepared and Ni film was thickened to 3μm by electroplating.Its optical properties and its influence on the infrared absorption of sodium nitrate were investigated. The results show that there is a transmission peak centered at 1 450 cm-1 under normal incidence,and the peak covered the fre-quencies ranging from 1 300 to 1 500 cm-1 ,the antisymmetric stretching vibration of nitrate.Moreover,the change of absorp-tion intensities of nitrate’s antisymmetric stretching vibration is essentially consisting with the transmittance of photonic crystal. It indicates that the absorption intensity of sodium nitrate is improved by the modulated infrared light.