Speckle decorrelation influence on measurements quality in vortex metrology

OPTICS COMMUNICATIONS

卷:285

Article

Angel-Toro, Luciano¹  Sierra-Sosa, Daniel^1,2,3  Tebaldi, Myrian^2,3  Bolognini, Nestor^2,3,4 

[1] Univ EAFIT, Dept Ciencias Basicas, Grp Opt Aplicada, Medellin, Colombia

[2] Ctr Invest Opt CIOp CONICET CIC, Manuel B Gonnet, Argentina

[3] UNLP, Fac Ingn, Dpto Ciencias Basicas, OPTIMO, Manuel B Gonnet, Argentina

[4] UNLP, Fac Ciencias Exactas, La Plata, Buenos Aires, Argentina

关键词: Speckle;    Vortex metrology;    Decorrelation;    Reisz transform;    Optical processing;    Fourier optics;   

DOI  :  10.1016/j.optcom.2012.07.021

来源: Elsevier

【 摘 要 】

We study speckle decorrelation effects in connection with conventional vortex metrology techniques. Our proposal is based on processing speckled images recorded by using two different experimental setups. In both schemes two laterally displaced patterns are generated: one scheme allows for obtaining undecorrelated speckle distributions and the other for decorrelated ones. Vortex networks associated with speckle patterns are analyzed by employing the usual tools developed for vortex metrology. For each recorded image, a 2D pseudo-phase map is generated on the basis of the Reisz transform. Then the vortices are located, and parameterized in terms of their topological charge, eccentricity, vorticity and angles between the zero crossing lines from the real and the imaginary parts of the analytical signal. After tracking the homologous vortices onto the maps, the histograms corresponding to the coordinate displacements are analyzed. We show that histograms interpretation is prone to failure due to its high sensitivity to decorrelation. Experimental evidences are presented to support the restrictions imposed by decorrelation of actual speckles due to uniform in-plane displacements. (C) 2012 Elsevier B.V. All rights reserved.

【 授权许可】

Free