Different from the method by plane-wave interference, here an efficient approach is proposed to generate optical vortex array (VA) based on lateral-shearing interferometer (LSI), in which the evolution from light spot array to VA can be observed by continuously variable shear ratio in a certain range. VAs with topological charge 2 and 1 are simulated by software GLAD and proved to be effectiveness through optical experiment. Theoretical analysis and experimental results show that when the shear ratio approaches to zero, we can stably obtain a vortex array with high density and variable topological charge.

Lateral Shearing Interferometer (LSI), as a kind of self-interference technology, can achieve high-precision wavefront sensing and phase imaging. Quadriwave Lateral Shearing Interferometry (QWLSI) divides the wavefront into four transverse dislocated beams by a checkerboard phase grating. The lateral-shearing interferogram of the four waves occurs on the image plane, and then the test wavefront is reconstructed. The reconstruction precision is determined by the shear ratio, thus the variable shear ratio can meet the requirement of the different measurement accuracy. Here we proposed variable-ratio lateral-shearing interferometry with a vortex-splitting grating. Different from the checkerboard grating, topological charge is first encoded into grating and is then optimized to obtain two shear ratios in the same interference setup. The proposed variable-ratio lateral-shearing setup including of only an axial motion device is robust, effective and variable precision for wavefront sensing.