对称结构光子晶体的表面光学Tamm态

Optical Tamm state on the surface of photonic crystal of symmetric structure

利用传输矩阵理论和等效原理,从能级的角度研究对称结构光子晶体表面光学Tamm态,结果表明:当光子晶体的排列周期无限大时,入射介质与光子晶体间不满足阻抗匹配条件,从而不出现表面光学Tamm态;当光子晶体被截断成有限周期时,其表面可支持表面光学Tamm态的存在,且轴向传播时通带中出现TM和TE偏振的能级简并现象,离轴传播时从通带边缘分离出来的非简并能级被局域于光子晶体表面而形成了表面光学Tamm态;当光子晶体截断参数与最外层高折射率介质匹配时,容易形成束缚性较强的表面光学Tamm态,与最外层低折射率介质匹配时,则难以实现表面光学Tamm态;通过ATR全反射技术对光子晶体表面态进行激发可观察到被激发的耦合共振吸收现象。对称结构光子晶体表面光学Tamm态的特性可为光子晶体光波导和表面波传感器的研究和设计提供指导。

Using transfer matrix and equivalent principle, the Tamm state on the surface of the symmetric photonic crystal was investigated in the new point of energy levels. The result shows that when the symmetric system is an infinite periodic structures for photonic crystal, there is impedance mismatch between incident medium and photonic crystal, thus the optical Tamm state on the surface doesn′ t exist. When the photonic crystals is truncated to finite period structure, it supports the appearance of the optical Tamm state on the surface, and the doubly degenerated energy level of TE and TM polarization appears in the energy band. In optical off-axis transmission, the optical Tamm state form the passband edge non-degenerated energy which is restricted on on the surface of photonic crystal. When the truncation parameter is matched with the high refractive index of outmost layer, it is easy to form a strong optical Tamm state. But when it is matched with the lower refractive index of outmost layer, it is difficult to realize the surface state. When the surface state of photonic crystal is excited by the ATR total reflection technique, the coupled resonance absorption can be observed. The properties of optical Tamm state on the surface of photonic crystal can provide guidance for research and design of optical waveguide or surface wave sensor.