Coherence of beam arrays propagating in the turbulent atmosphere

Abstract

We analyze some recent publications addressing propagation of the partially coherent polarized beams and beam arrays in the turbulent atmosphere. We show that the published results are limited to the scalar propagation model, and are not particular to the beam polarization. Therefore these results are equally relevant for the scalar beam pairs and arrays discriminated by some parameters such as small frequency shift, time delay or geometry, but not necessary the polarization. We use the virtual incoherent source model to derive the general form of the mutual coherence function of the two Schell-type beams. We discuss some physical stochastic models that result in the creation of the Schell-type beams and beam arrays. New classes of the uniformly, nonuniformly and nonlocally coherent beam pairs emerge naturally from this analysis. Rigorous, Markov approximation-based, propagation model provides relatively simple analytic results for the second-order moments of the optical field of the partially-coherent individual beams and beam pairs. We examine the changes of the beam mutual coherence in the process of the free-space propagation and propagation through the turbulent atmosphere.

Transverse linear and orbital angular momenta of beam waves and propagation in random media

“…Note that this 'constructive' approach' [26] to the coherence function formation guarantees its SPD property.…”

“…Clearly, ubiquitous Gaussian-Schell model beams form a specific case of the HCPC class of beam waves. As was discussed in [26], this type of wave is formed when radiation from a virtual incoherent source with spatial brightness distribution proportional to k L r c ˆ( ) passes through an aperture with complex transmission coeffi-…”

“…As was discussed in [25], this type of wave is formed when radiation from a virtual incoherent source with spatial brightness distribution proportional to   L kr  ˆ passes through an aperture with complex The TLM corresponding to Eq. ( 29) is calculated with the help of Eq.…”

“…It was shown in [25] that this partially coherent beam wave can be presented as a result of averaging of the randomly displaced and tilted collimated Gaussian beam…”

Spatial correlation properties of coherent array beams modulated by space-time random phase

“…For the primary purpose to improve radiation power, various types of partially coherent array beams and their spatial coherence through turbulent atmosphere have been widely investigated [5][6][7][8][9][10]. Notably, Ji et al first studied the spatial correlation properties and the spectral intensity distributions of focused Gaussian-Schell model (GSM) array beams and further discussed the beam quality of linear and radial GSM array beams [5,6].…”