Nonlinear optical detection of the orbital angular momentum of light

Optical beams carrying orbital angular momentum (OAM) have gained significant interest due to their unique properties, enhancing various communication systems and enabling applications such as the characterization of material or molecular chirality. Generating and detecting the OAM of light is thus crucial for numerous applications but poses challenges. This paper proposes a method utilizing stimulated Raman scattering to detect the magnitude of OAM. By exploring the strong Raman coupling between the pump and Stokes beams in higher-order Laguerre-Gauss modes, we demonstrate the discrimination of different optical vortex beams through nonlinear optical measurements. Numerical and experimental results support the feasibility of this approach, potentially advancing optical communication and sensing technologies.