电磁波在双零折射率光子晶体中奇异传播性质的研究

Recently, zero-index materials have become one of the hottest research topics in the field of metamaterials. New optical devices, such as arbitary shaped waveguide, arbitary wavefront engineering devices et. al., have been proposed based on zero-index material. In 2011, we designed and constructed the first double-zero-refractive-index photonic crystal, which exhibits simultaneous zero effective permittivity and permeability. Novel electromagnetic wave propagation properties, including arbitary waveguiding,focusing and cloaking in waveguide were demonstrated. However, many other intriguing and peculiar properties of this novel artificial material remain unexplored and unrealized. In this project, through theoretical analysis, numerical simulations and microwave experiments, we will carry out a series of studies on the double-zero-refractive-index photonic crystals. A new microwave waveguide with tunable transmission due to the defect state inside the waveguide will be developed. We will also understand the electromagnetic pulse propagation mechanism through this novel material. Further discussion will be conducted on how quasiperiodic or non-periodic structure will affect the electromagnetic properties of the double-zero-refractive-index photonic crystal. The physical mechanism behind the peculiar electromagnetic wave propagations in this novel artificial material is to be revealed. New microwave devices will be designed and constructed. A better understanding of this system will pave the road to the realization of new devices working at infared and even optical frequencies.

零折射率材料是最近超颖材料研究中的热点。利用零折射率材料可以构造新型光学器件，让电磁波沿任意路径传播，或任意改变电磁波波前形状。我们在2011年首次实现了有效介电常数和磁导率同时为零的双零折射率光子晶体，并展示了其具有弯波导，聚焦和一维隐身等新颖的功能。然而，这种新型材料仍有很多奇妙功能尚未实现，甚至未被探索过。本项目拟对双零折射率光子晶体系统开展进一步的研究，包括：1）研究缺陷态对双零折射率波导管中电磁波传播的影响；2）分析双零折射率光子晶体中电磁脉冲的传播特性；3）探讨准晶周期和非周期结构对双零折射率光子晶体电磁特性的影响等。我们希望通过理论分析，数值模拟和微波实验等多方面研究，深入探索并理解光在双零折射率光子晶体中的特殊传播性质，开发新型电磁波器件，并为将这一新领域推广到光学频段打下基础。

申请人的国家自然科学基金青年项目“电磁波在双零折射率光子晶体中奇异传播性质的研究”主要在理论和微波实验方面研究双零折射率光子晶体中存在的各种特殊电磁性质。由于介电常数和磁导率同时为零，此种零折射率材料的阻抗可以和空气匹配，且只需利用介质材料构建，加工制备都非常简便。因此具有广泛的应用前景。基于申请本项目主要完成了三个方面的工作：1）研究了填充零折射率材料的波导管中存在缺陷的情况下，二维和三维零折射率材料渗流特性的不同之处；2）研究了各向异性零折射率材料对电磁能流的操控能力，并在尝试利用光子晶体实现各向异性零折射率材料的同时，发现各向异性光子晶体可以拥有具空间色散的有效介电常数和磁导率，并利用介质光子晶体实现了超透明固体材料；3）研究了双零折射率光子晶体能带中狄拉克色散的拓扑性质，并通过能带调控，成功的实现了能带反转，并实现了确定性的光子晶体界面态并首次在实验上测出界面态色散。其中各向异性超透明介质材料以封面论文的形式在Phys. Rev. Lett.上得到发表。