Novo método para medição da largura de feixes gaussianos utilizando imagens de laser speckle

Abstract

This work introduces a novel method for measuring the beam waist of Gaussian laser beams using laser speckle analysis. By leveraging the inverse relationship between speckle grain size and beam size, the proposed approach achieves precise measurements through image processing and statistical analysis of speckle patterns. The methodology was validated by comparing results from speckle-based measurements with those obtained using direct imaging and a commercial slit-scanning beam profiler, demonstrating excellent agreement. Unlike conventional beam profiling methods, which are constrained by pixel resolution limitations, this technique resolved tightly focused beam waists as small as (1.87 ± 0.02) µm, smaller than the camera sensor pixel size. Furthermore, the static setup, free of moving parts, enhances stability and ensures reproducibility. This method highlights the advantages of the speckle-based approach for laser diagnostics and its potential to overcome the limitations of conventional profiling techniques.