Propagation Properties Of The Optical Coherence Lattice In Atmospheric Turbulence

In recent years,the laser beam has been widely used in free-space optical communication because of its low cost,high power and good directivity.However,temperature gradient and aerosol in the propagation of atmospheric turbulence cause the fluctuation of refractive index,which affects its beam quality.And with the development of the theory of partially coherent light,researchers have found that the partially coherent beams have remarkable advantages in resisting turbulence.At the same time,we find that the effects of atmospheric turbulence such as beam wander,intensity scintillation,wavefront distortion can be constrained by adjusting the parameters of partially coherent beams,e.g.waist width,coherence length,phase and polarization.In addition,in recent years,researchers have found that the beam arrays also have the effect of suppressing turbulence.At the same time,they are widely used in information encryption and particle capture because of their special shape distribution and special coherence characteristics.The optical coherent lattices(OCLs)introduced in this paper is also a special kind of beam array.It is a partially coherent beam with special correlation function.Special correlation means that the correlation function is a non-Gaussian function.Based on the basic theory of OCLs,the propagation characteristics of OCLs in atmospheric turbulence are analyzed by theoretical calculation and numerical simulation.The advantages of OCLs on propagation in atmospheric turbulence compared with Gaussian-Schell model beam(GSM)are also proved.The basic structure is concluded as follows:In Chapter 1,we will briefly introduce the development history and research background of partially coherent light,and briefly describe the establishment of turbulence theory and the progress in research of partially coherent light propagation in atmospheric turbulence.In Chapter 2,the basic theory of partially coherent light is introduced.Firstly,the theoretical model of partially coherent light is introduced,including mutual coherence function and cross-spectral density function.Secondly,the basic theory of the partially coherent beam propagating in atmospheric turbulence is proposed.We conclude several methods to solve wave equation in the atmospheric turbulence in the history,and we mention some fundamental parameters to characterize the performance of the partially coherent beam in the propagation in the atmospheric turbulence.In Chapter 3,we have reviewed the development the theory of OCLs.Firstly,we introduce two different theoretical models of OCLs.Then we introduce the experimental generation of OCLs by using the theoretical model,and obtain some properties of its propagation in free space and atmospheric turbulence through the model.In Chapter 4,a theoretical model of optical coherent vortex lattices(OCVLs)is proposed.The propagation characteristics of OCVLs in atmospheric turbulence are studied by investigating their several properties.We find that the influence of atmospheric turbulence on OCVLs can be effectively reduced by adjusting the parameters of the beams themselves.In Chapter 5,we make a summary and prospect of the research.