Modulating image oscillations in focusing by a metamaterial lens: Time-dependent Green's function approach

It was demonstrated previously that the image focused with an epsilon=mu=-1 metamaterial lens is intrinsically unstable, and adding absorption stabilizes the image at the price of degrading the image resolution. Here we show that a stable image with the highest possible resolution can be obtained in the shortest duration, if the source's "switching-on" time matches the intrinsic focusing speed of the lens. We demonstrate that the image oscillations, although appearing different and complicated in different situations, are all dictated by the interactions between the source spectra and the lens surface modes, and can be efficiently modulated by the lens thickness and the material parameters.