In 1992, Allen et al. firstly, to the best of our knowledge, demonstrated a helical phase structure of light with wavefront singularities carrying orbital angular momentum (OAM)^[1]. Such optical vortex (OV) beams characterized by the phase factor exp(ilθ), where l donates the OAM state or the topological charge (TC), and θ is the azimuthal angle, have been widely applied in various areas, including optical tweezers^[2], optical trapping^[3], optical communication^[4], and quantum information technology^[5]. Most of these applications require a specific TC. As a consequence, the determination of TCs is of crucial importance.