Using the characteristic of refractive index are smaller than 1 in the reststrahlen band,we can produce photonic crystal having forbidden band in the middle infrared and far infrared.

由此知利用材料在剩余射线带内折射率小于1的特性，以制备出中红外区和红外区存在禁带的光。

Incorporating array of metallic wires into the host media, such as ferrimagnet YIG under an external magnetic bias field, is a novel method to synthesize negative refractive index (NRI) material.

摘要以亚铁磁煤质-YIG为基，在其中嵌入金属导线阵列是人工合成负折射率微波媒质的一种新方法。