The topological charge measurement of the vortex beam based on dislocation self-reference interferometry

Vortex beam generally refers to a kind of beam with orbital angular momentum, which has been widely implemented in the field of optical trapping, optical communication, rotation detection, etc. The topological charge (TC) of the orbital angular momentum is a characteristic value of the vortex beam, and its detection is very important. Based on the misaligned self-reference interferometer, we propose a method to measure the TC of the vortex beam. The simulation and experimental results show that the proposed method can measure the TC accurately. This method does not require strict alignment or other additional reference beam to ensure the coherence of the two beams. In addition, the device itself can verify the measurement results based on the two bifurcation points in the interferogram.