Optical Cloak Design Exploiting Efficient Anisotropic Adjoint Sensitivity Analysis

We propose in this work a novel optimization-based wideband invisibility cloaking approach at optical frequencies. We exploit the memory efficient anisotropic adjoint variable method (AVM) to significantly accelerate the sensitivity analysis with respect to the large number of parameters. Minimizing the cloaking objective function involves the gradients estimation with respect to a massive number of parameters at every iteration for time-intensive electromagnetic simulations. The AVM evaluates the required gradients over one thousand time faster than conventional methods. The significant reduction in the computational cost enables wideband optimization-based cloak design at optical region.