Moment determination of light beams by using polynomial transmittance windows

Abstract A method for the measurement of the moments of a light beams is proposed here. This technique uses only one large area detector to collect, by means of a lens whose focus coincides with the detector plane, all the energy that passes through (or is reflected from) a variable transmittance (or reflectance) window. The detection system moves across the beam distribution and provides a signal that is a function of the relative position of the window and the beam. The moments are obtained from the polynomic fitting of this signal. The sensitivity of the method with respect to several experimental parameters is analyzed by means of numerical simulation.