Optical silver superlens imaging below the diffraction limit

Abstract

Conventional optical imaging systems cannot resolve the features smaller than approximately half the size of the working wavelength, called the diffraction limit. The superlens theory predicts that a flat lens made of an ideal material with negative permittivity and/or permeability is able to resolve features much smaller than working wavelength through the restoration of evanescent waves[l]. We experimentally demonstrated the superlens concept for the first time using a thin silver slab in a quasi-static regime; a 60nm half-pitch object was imaged with λ=365nm illumination wavelength, λ/6 resolution[3], and the imaging of 50nm half-pitch object under the same light source, λ/7, was also reported[4]. Here, we present mainly experimental studies of near-field optical superlens imaging. © 2006 Materials Research Society.