Propagation Properties Of Partially Coherent Beam Through A Turbulent Atmosphere

Generation and application of laser beams have induced rapid development of modernscience and technology, resulted in emerging some new disciplines and cross-disciplines,and promoted the development of laser material processing, optical communication andremote sensing in atmosphere. The propagation and transformation of laser beams throughvarious media and optical system play an important role in laser physics and laserapplications.Partially coherent light is widely existed in practice. Completely coherent andcomplete incoherent light does not exist in a strict sense. Partially coherent light has beenwidely used in material thermal processing by laser beam and inertial confinement fusionby laser etc. The description of partially coherent light and their propagation andtransformation have been widely studied for a long time.Recently, more and more attention is being paid to partially coherent flat-topped beamdue to its important application in material thermal processing, optical trapping and freespace optical communications. In this paper, we propose propagation factor of a truncatedpartially coherent flat-topped beam in turbulent atmosphere and M2-factors of anon-circular partially coherent flat-topped beam in turbulent atmosphere.First, our aim is to investigate the properties of the propagation factor of a truncatedpartially coherent FT beam in turbulent atmosphere based on the extended Huygens–Fresnel integral and the second-order moments of the Wigner distribution function.Analytical expression for the M2-factor is derived. Some numerical examples areillustrated.Second,the purpose is to investigate the properties of the M2-factors of a non-circular(i.e., rectangular or elliptical) partially coherent flat-topped beam in turbulent atmosphereand in free space comparatively. Some interesting and useful results are found.