Inverse design of invisibility cloaks using the optical theorem

We develop and apply an optimization method to design unidirectional invisibility cloaks. Our is based on minimizing the forward scattering amplitude of cloaked object which, by optical theorem, equivalent total cross section. The use theorem circumvents need evaluate integrate over angle at each iteration, thus provides a simpler, more computationally efficient objective function optimize structures. implement approach using gradient descent present several gradient-permittivity cloaks that reduce metallic targets different sizes shapes.