负-零-正折射率超常介质平板结构中的透射横向位移特性分析

Lateral shifts of transmission light from slab structure with negative-zero-positive index metamaterial

针对光波在负-零-正折射率超常介质平板结构中的传播,利用Artmann的稳态相位法研究了光学Dirac点附近的透射横向位移特性。讨论了横向位移随入射角度、频率和平板厚度的变化关系,发现该结构中的横向位移可以达到波长的几十甚至几百倍之多并且在Dirac点附近能够实现正负变化。进一步研究了全反射情形下的横向位移特性和光子隧穿现象、证实了横向位移的Hartman效应。另外,由于材料的特殊线性色散,发现横向位移在靠近临界角时,随着角度增大而减小;而在远离临界角时随着角度增大而增大。研究结果将在集成光学和光学器件方面产生应用可能,也将进一步促进石墨烯量子结构中电子传播的类光学现象研究。

For light waves propagating in a slab structure with a negative-zero-positive index metamaterial in the core, properties of the lateral shifts of the transmission light were investigated in detail by employing Artmann＇s stationary phase method. The results show that, near the Dirac point（DP）, the lateral shift can vary from positive to zero then to negative and is dozens of times even hundreds of times higher than the wavelength, which is strongly dependent on the incident angle, frequency, and the thickness of the metamaterial. For the slow wave mode, the lateral shifts and the photon tunneling were further studied. Because of the Hartman effect, the lateral shift tends to a saturation value when the barrier thickness increases, and displays different properties when the incident angle chosen near and far away from the critical angle. These results may lead to potential applications in integral optics and optical-based devices and also suggest analogous phenomena of valance electron in single-layered carbon graphene.