Propagation of beams with any spectral, coherence and polarization properties in turbulent atmosphere

The combination of the angular spectrum representation (in space-frequency domain) and of the Rytov perturbation theory is applied for description of the second-order statistical properties of arbitrary (coherent and partially coherent) stochastic fields (whether scalar or electromagnetic) which propagate in turbulent atmosphere. The analysis is restricted to weak regime of atmospheric fluctuations. We first introduce the new method for scalar fields and derive expressions for the cross-spectral density function, from which the spectral and the coherence properties of the propagating fields can be determined. Next we extend the new technique to electromagnetic domain, i.e. we derive expressions for the elements of the 2x2 cross-spectral density matrix of the electric field from which its spectral, coherence and polarization properties can then be found. We illustrate the new method by applying it to propagation of several model beams through the atmosphere. In particular, we consider Gaussian beam, Bessel beam, Gaussian Schell-model beam in their scalar or electromagnetic versions. We find that the results obtained on the basis of the new theory are in good agreement with those obtained earlier by standard techniques.