Cloak of arbitrary shape

We propose a segmentation design approach for a cloak of arbitrary shape. We suggest that polygonal 2D cloaks with any number of sides, which do not require geometrical symmetry, can be achieved by dividing the polygon into many triangular regions and applying a spatial transformation on each triangle. This idea is verified by full-wave finite-element-based simulations, showing electromagnetic waves smoothly guided around cloaked perfect-conducting cylinders with different shapes of cross sections. This segmentation-transformation method can be well extended to cloaking of arbitrary shapes, including 3D cases. As an example, we simulate a cylindrical cloak whose cross section is very close to the contour of a woman, which demonstrates the validity of our method and further confirms the power of transformation optics. (C) 2008 Optical Society of America