title: Ideal cylindrical cloak: perfect but sensitive to tiny perturbations.
abstract: A cylindrical wave expansion method is developed to obtain the scattering field for an ideal two-dimensional cylindrical invisibility cloak. A near-ideal model of the invisibility cloak is set up to solve the boundary problem at the inner boundary of the cloak shell. We confirm that a cloak with the ideal material parameters is a perfect invisibility cloak by systematically studying the change of the scattering coefficients from the near-ideal case to the ideal one. However, because of the slow convergence of the zeroth-order scattering coefficients, a tiny perturbation on the cloak would induce a noticeable field scattering and penetration.
authors.affiliation: Laboratory of Optics, Photonics and Quantum Electronics, Department of Microelectronics and Applied Physics, Royal Institute of Technology (KTH), Electrum 229, 16440 Kista, Sweden.
authors.forename: Zhichao
authors.initials: Z
authors.lastname: Ruan
authors.forename: Min
authors.initials: M
authors.lastname: Yan
authors.forename: Curtis W
authors.initials: CW
authors.lastname: Neff
authors.forename: Min
authors.initials: M
authors.lastname: Qiu