Resolving images by blurring: superresolution method with a scattering mask between the observed objects and the hologram recorder

Abstract

An important quest in optical imaging has been, and still is, extending the resolution of imaging systems beyond the diffraction limit. We propose a superresolution technique in which the image is first blurred by a scattering mask, and then recovered from the blurry data with improved resolution. We introduced a scattering mask into the space between the observed objects and the objective lens of a Fresnel incoherent correlation holography (FINCH) system to demonstrate the method. Optical waves, containing high spatial frequencies of the object, which are usually filtered out by the limited system aperture, were introduced into the system due to the scattering nature of the scattering mask. As a consequence, both the effective numerical aperture and the spatial bandwidth of the system were enlarged. The image resolution could therefore be improved far beyond the resolution limit dictated by the limited numerical aperture of the system. We demonstrated the technique using a modified FINCH system and the results were compared with other systems, all having the same aperture dimensions. We showed a resolution enhancement in comparison to conventional FINCH and regular imaging systems, with the same numerical apertures. The theoretical and experimental data presented here establishes the proposed method as an attractive platform for an advanced superresolution system that can resolve better than conventional imaging systems.