Phase distribution measurements of Laguerre-Gaussian beam with Fourier transform fringe analysis and polarization methods

In this paper we compare two methods for the measurement of phase distribution of LG beams. The first method is interference fringe analysis by Fourier transform. This method deliberately introduces a tilt between the measured LG beam and reference beam, creating fine interference fringes with a roughly constant pitch across the measurement plane. The phase distribution is extracted from the spatial modulation to these carrier fringes using Fourier transform and filtering. The second method combines polarization and interference, allows the determination of phase pixel by pixel.