According to the present invention, many metamaterial devices requiring anisotropic dielectric permittivity and magnetic permeability could be emulated by specially designed tapered waveguides. This approach leads to low-loss, broadband performance in the visible frequency range, which is difficult to achieve by other means. We apply this technique to electromagnetic cloaking. We demonstrate broadband, two-dimensional, electromagnetic cloaking in the visible frequency range on a scale roughly 100 times larger than that of the incident wavelength.
 
It looks like a kind of controlled optical destructive interference effect.  To read more, click here.