Self-healing of orbital angular momentum in bright twin light beams generated via four-wave mixing

The utilization of orthogonal modes of structured light, such as orbital angular momentum (OAM), in optical communication has led to an increased focus on the self-healing property of beams that contain OAM. In this paper, we theoretically and experimentally investigate the self-healing property in the twin Laguerre-Gaussian (LG) beams generated with a truncated input pump or probe having LG profiles in a four-wave mixing process in a double-$\mathrm{\ensuremath{\Lambda}}$ configuration. We show that, along with the amplified probe, the newly generated conjugate beam also acquires the truncated profile and exhibits self-healing on propagation. The transverse spatial intensity is reconstructed, and the OAM associated with the topological charge of the beams is restored in the far field. The self-healing in the generated beams is also studied for different topological charges and different obstacle types. The experimental results are supported with a theoretical model based on the semiclassical approach. The results of the present paper hold promise for practical implementation in real-world applications such as quantum communication and information transfer with OAM modes, addressing critical challenges like losses due to obstructions.