折射率梯度表面机理的研究

本文构建了一种折射率梯度表面,并利用几何光学法对其物理机理作了研究,发现这种折射率梯度表面可以实现入射波到正常反射波,异常反射波,以及介质波的转换.当入射点介质折射率大于某一阈值时,异常反射波束方向角正弦值与入射波束方向角正弦值存在线性关系,意味着平行入射的波经介质后将平行出射到空气;而当折射率梯度常数大于某一阈值时,任何方向入射的波在透射到介质后,将发生全反射,被束缚在介质中.总而言之,通过调节结构参数,可以实现对波束方向与强度的人工调控,从而提供了一种人工可控的全介质梯度表面的工程实现思路.

Studies on the mechanism of refractive index gradient surface

These years, with the development of material fabrication technology, some new synthetic materials that have unique electromagnetic properties have come out, one of which, the gradient meta-surface constructed into a special topological structure, gains rising popularity among experts. This paper establishes a refractive index gradient meta-surface and discusses its physical mechanism in optics. Normal reflection, anomalous reflection, and transformation from plane wave to medium wave can be realized by using this meta-surface. If the refractive index is larger than some threshold, the sine value of the reflection angle will vary linearly with that of the incidence angle, implying that parallel incident waves will become parallel emergent waves. If refraction index gradient is larger than some threshold, the plane wave at any incidence angle will give out a total reflection inside the medium, in other words, it is bound within the medium. Therefore the control of direction and intensity of beams can be achieved by adjusting parameters, providing a new engineering implementation method of artificial controllable full-medium gradient meta-surface.
Keywords：refractive index gradient on the surfacegeometrical optic methodlinear relationtotal reflection