The superposition of Laguerre-Gaussian guided into and scattered by a particle in a rotated fluid allows the detection of the rotational of the fluid. The presented system allows for virtually real-time determination of vorticity characterization in a fluid. The system allows the direct measurements of fluid flow vorticity using a spatially shaped beam with a superposition of Laguerre-Gaussian modes that reports on the rotational Doppler shift from microparticles intersecting the beam focus.