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/μe and the measurement range is 0～2000 μe.