Sub-Rayleigh resolution single-pixel imaging using Gaussian- and doughnut-spot illumination.

In this paper, we propose an approach to achieve a sub-Rayleigh resolution image in a single-pixel imaging system. In our scheme, Gaussian- and doughnut-shaped spots are used to alternatively illuminate an object and a single-pixel detector located after the object is employed to collect the transmitted light as two bucket signals, respectively. The image is reconstructed by assigning the difference of the bucket signals to the central position of the illumination spot. In this way, the spatial resolution of the resulting image is determined by the width of subtraction of the two spots. Combined with the deconvolution algorithm, we achieve a spatial resolution beyond the Rayleigh limit of single-pixel imaging by a factor of 22. We also propose a differential algorithm to keep the visibility of single-pixel imaging at a high level, which will be more suitable for applications.