Sub-Nyquist label-free fiber-based ghost imaging

Fiber optics provides a compact endoscopy probe, which can look deep inside the tissue [1] . However, conventional microscopy techniques, including fiber-based, are limited by diffraction. The majority of super-resolution techniques rely on the fluorescent labeling of the sample [2] . In contrast, computational ghost imaging (CGI) via sparsity constraint overcomes the diffraction limit without exploiting any specific properties of the fluorescent label [3] . By illuminating the sample with a set of nearly orthogonal intensity patterns and measuring the transmitted intensity, one can numerically reconstruct the sample transmission function with the resolution limited neither by the diffraction nor by Nyquist limits [4] .