Influence of turbulence on the coherent and incoherent combinations of off-axis Gaussian beams

Abstract

The influence of turbulence on the coherent and incoherent combinations of off-axis Gaussian beams is studied in detail. The analytical propagation equation of the resulting beam in turbulence for the incoherent combination is derived. The mean-squared beam width, the power in the bucket and the β parameter are taken as the characteristic parameters of beam quality to compare the results of coherent and incoherent combinations of off-axis Gaussian beams propagating through atmospheric turbulence, and the reasonable physical explanations are also given. It is shown that, on one hand, both for the incoherent and coherent combinations the turbulence results in a beam spreading and a degradation of the maximum intensity, and the larger the individual beam numbers is, the less sensitive is the resulting beam to the effect of turbulence. On the other hand, the resulting beam for the incoherent combination is less affected by turbulence than that for the coherent combination.