Fluid mechanics measurement based on the anisotropic core structure of pseudophase singularities in analytic signal representation of speckle pattern

摘要

A new technique for fluid mechanics measurement is proposed that makes use of pseudophase singularities in an analytic signal representation of a speckle-like pattern generated by a Laguerre-Gauss filter operation. Based on the formal analogy between the polarization of the vector wave and the gradient field for the complex analytic signal, a set of Stokes-like parameters have been applied for the description of the anisotropic core structure of the pseudophase singularities, which serves as unique fingerprints attached to the seeding particles moving with the flow. Experimental results for flow velocity and acceleration measurement are presented that demonstrate the validity of the proposed optical vortex metrology for fluid mechanics measurement.