Limits on the amplification of evanescent waves of left-handed materials

We investigate the transfer function of the discretized perfect lens in finite-difference time-domain (FDTD) and transfer matrix method (TMM) simulations; the latter allow to eliminate the problems associated with the explicit time dependence in FDTD simulations. We also find that the finite discretization mesh acts like imaginary deviations from mu=epsilon=-1 and leads to a crossover in the transfer function from constance to exponential decay around k(parallel to,max) limiting the attainable super-resolution. We propose a simple qualitative model to describe the impact of the discretization. k(parallel to,max) is found to depend logarithmically on the mesh constant in qualitative agreement with the TMM simulations. (c) 2006 Optical Society of America.