Experimental realization of breaking diffraction limit by planar negative-index metamaterials in free space

The sharpness of the image formed by a conventional lens is always limited by the wavelength of light. Recently, Pendry proposed a superlens, with a negative refractive index, such that the resolution is not limited by wavelength. Herein, we report direct experimental evidence of Pendry's superlens breaking the diffraction limit, in the microwave range of the X band (8–12 GHz), with a periodic array of split ring resonators and continuous wires; i.e. a meta-material with negative index of refraction.