Super-resolution far-field sub-wavelength imaging using multiple holography

Losing the information contained in evanescent waves scattered from an object limits the best achievable resolution in far-field optical imaging systems to about half of the wavelength. This limitation is known as the diffraction limit. In this paper, we propose a new holography-based far-field imaging technique to go beyond the diffraction limit and achieve super-resolution images. In the proposed method, after the recording process, multiple reconstruction processes with appropriate reconstruction waves are performed to extract information about subwavelength features of a target object encoded in the evanescent waves scattered from it. It is analytically proved that in the proposed method, by increasing the number of reconstruction steps, the resolution increases. The performance of the method is numerically validated. In numerical analysis, by performing two reconstruction steps, a resolution of 1/14 of the working wavelength is achieved. This resolution can be further improved by increasing the number of reconstruction steps. (C) 2021 Optical Society of America