Guoyan Dong, Ke Bi, Ji Zhou, Xiulun Yang, Xiangfeng Meng
Opt Express. 2013 Dec 2;21(24):29860-6. doi: 10.1364/OE.21.029860.
Based on the wavefront modulation of photonic crystal (PhC), zero phase delay of propagating electromagnetic wave (EMW) can be realized with a relaxed incident condition in the PhC. The phase velocity is modulated perpendicular to the group velocity with wavefronts extending along the direction of energy flow, which lead to the phenomenon of zero phase delay with a finite spatial period. This effect can be realized simultaneously in both positive and negative refracted waves. The phase difference between the incident and transmitted waves are measured within a wide incident angle region to demonstrate zero phase delay can be realized easily instead of zero-n or zero-averaged-n materials. Further investigations prove that the phenomena of zero phase delay induced by this way can also be realized easily in various PhC configurations and can be accurately manipulated by changing the incident angle or the flexible design of PhC configuration.
基于光子晶体（PhC）的波前调制，在光子晶体中可以通过放宽入射条件来实现传播电磁波（EMW）的零相位延迟。相速度垂直于群速度进行调制，波前沿能量流方向延伸，这导致了具有有限空间周期的零相位延迟现象。这种效应在正折射波和负折射波中都能同时实现。在宽入射角区域内测量入射波和透射波之间的相位差，以证明可以轻松实现零相位延迟，而无需零折射率或零平均折射率材料。进一步的研究证明，通过这种方式诱导的零相位延迟现象在各种光子晶体结构中也能轻松实现，并且可以通过改变入射角或灵活设计光子晶体结构来精确控制。
