An Efficient Tensor Approach For Analyzing The Propagation Of Partially Coherent Beams In Turbulent Atmosphere

A tensor approach to simulate and predict the transverse intensity and distribution of a two-point correlation of beams of arbitrary shape and coherence through atmospheric turbulence has been derived on the basis of the extended Huygens–Fresnel principle.The validity of this approach is verified by comparing the reconstructed intensity and second-order correlation of symmetric points in the output plane of a Gaussian Schell-model beam with calculated results from analytic formulae.An example illustrates how this tensor approach can be applied to beams blocked by finite apertures in the atmospheric propagation.Our approach provides an efficient and universal numerical model to manage the turbulent propagation of various optical sources.This approach can be useful in long-distance imaging and optical communication.The paper mainly includes the following four parts:1.The background of the propagation of light beams in atmospheric turbulence is introduced,and the second-order statistical properties of partially coherent beams are introduced in detail,and some basic knowledge of atmospheric turbulence is introduced.2.An effective tensor approach(ETA)for studying the propagation problem of partially coherent beams is introduced.The ETA algorithm is extended to an effective tensor approach(turb-ETA)from the theoretical point of view,turb-ETA can calculate the propagation of any type of partially coherent beams in atmospheric turbulence.Then the turb-ETA is used to calculate the average light intensity and second-order correlation of the partially coherent beam in the turbulent atmosphere,and then the calculated results of the turb-ETA are compared with the traditional analytical results,and the correctness of the algorithm is demonstrated.The algorithm is compared with the discrete Fourier transform method(DFT),which shows that the turb-ETA is not subject to the constraints of sampling constraints.Finally,the computational efficiency of several different algorithms is compared,and explain the advantages of turb-ETA in terms of computing speed.3.The Gaussian vortex beam and the rectangular cosine Gaussian mode beam are introduced,and the turb-ETA algorithm is used to simulate the propagation of these two beams in atmospheric turbulence,the wide applicability of the algorithm and some effects of turbulence on beam propagation are illustrated,and then the Gaussian mode beam is transmitted through a rectangular square hole.4.The intensity scintillation of partially coherent beams propagating in atmospheric turbulence is introduced.The method of calculating the scintillation index by turb-ETA is theoretically derived,the calculation results are analyzed,and the conclusion that the vortex and the high-order beams can reduce the light intensity scintillation is obtained.