Publication No: 3932

Optical super-resolution through super-oscillations

F.M.Huang¹, V.Fedotov¹, Y.Chen², F.J.Garcia de Abajo³, N.I.Zheludev¹

1. EPSRC Nanophotonics Portfolio Centre, Optoelectronics Research Centre, University of Southampton, UK
2. Central Microstructure facility, Rutherford Appleton Laboratory, Didcot, Oxon, OX11 OQX, UK
3. Instituto de Optica - CSIC, Serrano 121,28006 Madrid, Spain

Abstract

Most ideas for achieving super-resolution in optics are based on the recovery of evanescent fields which are commonly believed to be the necessary components to form subwavelength field concentrations. For instance, the famous Veslago-Pendry idea for a far-field super-lens is based on the recovery of evanescent information by "amplifying" the fading evanescent components in a slab of a negative-index material. However, evanescent fields may not be needed to achieve subwavelength concentration of light: according to a phenomenon called superoscillations, band-limited functions are able to oscillate arbitrarily faster than the highest Fourier components they contain.

Here we present experimental demonstration and theoretical analysis of optical superoscillation generators based on ID arrays of nano-holes and slits, and on 2D array of nano-holes in metal screen and show that they generate sub-wavelength localizations of light.

We also show that properly designed arrays of nano-holes can be used as a far-field imaging super-lens thus opening a new way of achieving optical resolution beyond Rayleigh limit, which is different from many existing approaches depending on the recovery of evanescent fields.

Progress in Electromagnetics Research Symposium (PIERS) Hangzhou, China 24-28 Mar (2008)