Level set based topology optimization for optical cloaks

• Published in: Applied physics letters Vol. 102; no. 25
• Main Authors: Fujii, Garuda, Watanabe, Hayato, Yamada, Takayuki, Ueta, Tsuyoshi, Mizuno, Mamoru
• Format: Journal Article
• Language: English
• Published: 24-06-2013
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4812471

This letter presents a level set-based topology optimization method that provides discrete cloaking configurations with superior performance. In some cases, the amount of light scattered around the two-dimensional cloaking structures is less than one-tenth that obtained in previous studies. Optimal configurations that express different geometrical characteristics can be obtained by adjusting a regularization parameter. The obtained configurations are free from grayscales, areas of intermediate density between that of dielectric materials or air, and the use of a level set method provides clear structural boundaries. The level set functions are given on grid points and the dielectric boundaries are interpreted as lines on the iso-surface of the level set functions. The finite element method is used for light scattering analyses, computations of the adjoint variable field, and when updating the level set functions.