Halimeh Jad C, Wegener Martin
Physics Department, Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München, D-80333 München, Germany.
Opt Express. 2012 Jan 2;20(1):63-74. doi: 10.1364/OE.20.000063.
As invisibility cloaking has recently become experimental reality, it is interesting to explore ways to reveal remaining imperfections. In essence, the idea of most invisibility cloaks is to recover the optical path lengths without an object (to be made invisible) by a suitable arrangement around that object. Optical path length is proportional to the time of flight of a light ray or to the optical phase accumulated by a light wave. Thus, time-of-flight images provide a direct and intuitive tool for probing imperfections. Indeed, recent phase-sensitive experiments on the carpet cloak have already made early steps in this direction. In the macroscopic world, time-of-flight images could be measured directly by light detection and ranging (LIDAR). Here, we show calculated time-of-flight images of the conformal Gaussian carpet cloak, the conformal grating cloak, the cylindrical free-space cloak, and of the invisible sphere. All results are obtained by using a ray-velocity equation of motion derived from Fermat's principle.
由于隐形衣最近已成为实验现实，探索揭示其剩余缺陷的方法就变得很有趣。本质上，大多数隐形衣的理念是通过在物体周围进行适当布置，恢复没有该物体（要使其隐形的物体）时的光程长度。光程长度与光线的飞行时间或光波积累的光学相位成正比。因此，飞行时间图像为探测缺陷提供了一种直接且直观的工具。事实上，最近对地毯隐形衣进行的相敏实验已经在这个方向上迈出了早期步伐。在宏观世界中，飞行时间图像可以通过光探测和测距（激光雷达）直接测量。在这里，我们展示了共形高斯地毯隐形衣、共形光栅隐形衣、圆柱形自由空间隐形衣以及隐形球体的计算飞行时间图像。所有结果都是通过使用从费马原理推导出来的光线速度运动方程获得的。
