一维光子晶体的应变测量

采用ZnSe和Na3AlF6两种经典介质材料构造一维光子晶体,缺陷层介质为Na3AlF6。利用传输矩阵法对带有缺陷的一维光子晶体的传光特性进行了理论分析,并得到其带隙特性。分别数值研究了参考光子晶体以及应变前后测量光子晶体的透射谱,分析结果表明光子晶体所受的纵向应变与其缺陷峰波长之间呈线性关系,根据这种对应关系提出了一种新的测量应变的方法。由于粘贴光子晶体的基底与光子晶体的线膨胀系数不同,且温度变化也会引起构成光子晶体材料折射率的变化,导致光子晶体透射谱缺陷峰波长的漂移。为了消除温度误差,在测量光路中设置了与测量光子晶体结构相同的参考光子晶体,对温度的影响进行了补偿。实验表明,测量系统的灵敏度为6×10-4nm/με,测量范围为0～2000με。

Strain-Measurement of One-Dimensional Photonic Crystal

ZnSe and Na3AlF6 as two classical materials are composed of one-dimensional (1D) photonic crystal, and the medium of the defect is Na3AlF6. Using transfer matrix method, the optical transmission properties in 1D photonic crystals with defect is analyzed, and the band gap property of 1D photonic crystal is obtained. The transmission spectra of reference photonic crystal and measurement photonic crystal with or without adding strain is simulated numerically. The analysis shows that it is linear relationship between the longitudinal strain and wavelength of the peak of band gap. According to the corresponding relation, a new method of strain measurement is presented. The wavelength of the peak of band gap can shift because the linear expansion coefficient between substrate and photonic crystal is not equal and the medium reflection index varies along with the temperature. In order to compensate temperature error, a reference photonic crystal having the same structure as the measurement photonic crystal is introduced in the measurement system. And the temperature compensation with a reference photonic crystal is realized. The results show that the sensitivity of this measuring system is 6×10-4 nm/με and the measurement range is 0～2000 με.