色散SiO2/TiO2薄膜组成的Fibonacci序列一维光子晶体在可见光波段的传输特性

用特征矩阵法研究了由正常色散SiO₂/TiO₂薄膜组成的Fibonacci序列一维光子晶体在可见光波段的传输特性,并与无色散时的传输特性做了对比。结果表明,随序列项数的增加,相应的前一序列的透射谱中透射率较低的凹带逐渐变成禁带,禁带数增加;初始介质是低折射率的SiO₂薄膜时比高折射率的TiO₂薄膜时各序列的透射谱中的禁带数多,各禁带的宽度和中心波长基本相同;在总厚度一定的条件下,随SiO₂薄膜的厚度增大（TiO₂薄膜的厚度减小）,禁带的宽度减小,禁带的中心波长基本不变;随入射角增大,禁带的中心波长向短波方向移动,禁带宽度变小。在其它相同条件下,无色散时的最宽禁带和最宽禁带的中心波长比有色散时的最宽禁带和最宽禁带的中心波长都有增加。

Transmission properties of 1-D Fibonacci sequence photonic crystals made up of dispersive SiO2/TiO2 thin films in visible region

The transmission properties of the 1 D Fibonacci sequence photonic crystals made up of dispersive SiO2 and TiO2 thin films in visible region are investigated by an eigen matrix method, and the results are compared with that without dispersion conditions. The comparison results show that the number of band gaps increase with the increases of the sequence terms. Moreover, the number of band gaps in transmission spectra from initial media in SiO2 thin films are higher than those of from initial media in TiO2 thin films. When the total physical length keeps a constant, the width of the band gap becomes narrower as the increase of the length of SiO2thin film, but the central wavelength of the band gap is a constant. Furthermore, the central wavelength of the band gap becomes shorter and the width of the band gap becomes narrower as the increase of the incident angle. When the dispersion is ignored, both the widest band gap and the central wavelength of the widest band gap have been increased. The conclusions can contribute to the study on the effect of dispersion on photonic crystals.