Stimulated Raman Scattering with Optical Vortex Beams

Abstract

This study investigates stimulated ramran scattering (SRS) with optical vortex beams, specifically Laguerre–Gaussian (LG) modes, characterized by distinct radial and azimuthal indices. SRS microscopy, particularly with label-free imaging capability, has become crucial in bioimaging; however, its spatial resolution remains limited by the diffraction limit, driving interest in super-resolution techniques with structured light. While recent advancements suggest promising approaches, nonlinear Raman interactions involving LG vortex beams remain underexplored. Here, the exact analytical expressions for SRS signals are derived by expanding one of the beams as a series of LG modes of the other and integrating Laguerre polynomials and product LG modes. The findings reveal that the SRS signals critically depend on the topological and hyperbolic momentum charges of the LG pump and Stokes beams. These results establish a quantitative framework for coherent Raman scattering processes induced by tailored and focused vortex beams, providing a theoretical foundation for applications in biological and material imaging as well as in the nonlinear optical detection of light's orbital angular momentum employing coherent Raman scattering measurement techniques with toroidal beams.