  Recently Merlin and co-workers demonstrated, both theoretically and in the
microwave range experimentally, subwavelength focusing of evanescent waves by
patterned plates. The present paper extends these ideas and the design
procedure to scatterers of arbitrary shapes and to the optical range of
wavelengths. The analytical study is supported by numerical results. The most
intriguing feature of the proposed design is that, in the framework of
classical electrodynamics of continuous media, focusing can in principle be
arbitrarily sharp, subject to the constraints of fabrication.
