Fluid flow vorticity measurement using laser beams with orbital angular momentum

TL;DR

This paper introduces a novel optical method using Laguerre-Gaussian laser beams to directly measure fluid flow vorticity in real-time, demonstrating high accuracy and potential for localized flow analysis.

Contribution

It presents a new technique employing orbital angular momentum beams for direct, real-time vorticity measurement in fluid flows, validated through experiments.

Findings

Accurate vorticity measurements with 200 ms integration.

Excellent agreement with theoretical vorticity values.

Method enables localized, real-time flow analysis.

Abstract

We report on 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. Experiments are carried out on fluid flows with well-characterized vorticity and the experimental results are found to be in excellent agreement with the expected values even for 200 ms integration times. This method allows for localized real-time determination of vorticity in a fluid flow.