Superresolved common-path phase-shifting digital inline holographic microscopy using a spatial light modulator.

Common-path phase-shifting lensless holographic microscopy has been recently proposed as a novel approach capable of high numerical aperture imaging in a lensless digital inline holographic microscopy layout [Opt. Lett.35, 3919 (2010)]. Here we present proof-of-concept validation for improving the resolution limit imposed by diffraction in such a setup. This is accomplished by shifting the phase lens displayed at the spatial light modulator, which moves the illumination point source to different off-axis positions. For each off-axis position, a set of inline phase-shifted holograms are recorded by the digital sensor and stored at the computer's memory for later digital postprocessing. As a consequence, each recording allows the recovery of different spatial frequency content of the object's diffracted wavefront meaning a superresolved image of the input object. Experimental results are reported validating the proposed method.