Subwavelength optical imaging of evanescent fields using reflections from plasmonic slabs.

Reflection can significantly improve the quality of subwavelength near-field images, which is explained by appropriate interference between forward and reflected waves. Plasmonic slabs may form approximate super-mirrors. This paper develops general theory in both spectral and spatial representations that allows the reflector position and permittivity to be determined for optimum image uniformity. This elucidates previous observations and predicts behaviour for some other interesting regimes, including interferometric lithography.