Shack-Hartmann measurements of the transverse linear and orbital angular momenta after propagation through turbulence

摘要

Theory presented in the companion paper [1] reveals that for paraxial propagation of scalar waves transverse linear momentum (TLM) and orbital angular momentum (OAM) of beam waves are simply related to the wave coherence function, and that the TLM and OAM densities can be measured by a conventional Shack-Hartman sensor, which is typically used for the phase measurements. Here we present the extension of this theory to the case of the OAM fluctuations of a spherical wave intercepted by a finite aperture. We report the OAM measurements derived from the data obtained by the Hartman Turbulence Sensor (HTS) during the field measurement campaign in 2009-10 and data produced by wave optics simulation of the HTS. We examine the statistics of the total OAM intercepted by the wave front sensor aperture and compare it to theoretical results. Modeling data supports the conservation of the mean OAM and relatively slow development of the OAM fluctuations predicted by the theory.