Integrating 5 × 5 Dammann gratings to detect orbital angular momentum states of beams with the range of −24 to +24

Abstract

The 5×5 2D binary Dammann vortex grating can distribute energy among different diffraction orders equally and can realize measurement of orbital angular momentum (OAM) states from -12 to +12. Here we combine a 5×5 Dammann vortex grating and a spiral phase plate with the order +12 or -12, which makes the topological charge of beams in the array increase or decrease by 12; thus, the range of measuring OAM states can be extended to a range from -24 to +24. We upload the holograms of such gratings on a liquid crystal spatial light modulator to do the experiment. The experimental results fit well with the simulation results. This method is also effective for multiplexed OAM beams and can be used in optical communications in the future.