Propagation Properties Of Vortex Beam In Turbulent Atmosphere

Recently,the vortex beam has special spiral phase structure which make orbital angular momentum.It presents small spots on the phase singularity.These characteristics make it widely used in optical micro manipulation, information transmission, biological medicine, quantum coding and other fields.Especially in the field of space optical communication which has more potential application value.Investigation on the transmission characteristics of vortex beam propagating in the atmospheric turbulence is one of the most interesting research field about the free space communication. Atmospheric turbulence has serious influence on vortex beam propagating in atmosphere turbulence, which can cause scintillation, beam drift and beam spreading. Scintillation is the basic problem about the turbulence effect, which is important to the laser radar detection in atmosphere, atmospheric parameters measurement, adaptive optics Hartmann wavefront detection sensor and laser communication.Based on the numerical simulation method,the establishment of simulation make the atmospheric channel as random phase screen. We use elliptic vortex beam, laguerre-gaussian vortex beam and poincare vortex as the research object.the strength of the atmospheric turbulence and the beam parameters is studied on the performance of the vortex beam propagation in the atmospheric turbulence.Through the specific numerical simulation experiment results show that the strength of the atmospheric turbulence will flicker index in the transmission process of vortex beams caused obvious changes, when turbulent structure often orders of magnitude greater than the 10 to-17, light intensity fluctuation is influenced by turbulence generated significant changes;Topological charge and beam waist width of vortex beams in atmospheric turbulence will impact scintillation index;When its topology is bigger,the transmission in the turbulent atmosphere flare shape keeping degree is higher,also its performance is more stable;The beam waist width which is the greater, the beam under the influence of turbulence degree is smaller.In the process of transmission, phase also showed a trend of screw rotation, the direction of rotation is closely related to the topological charge of plus or minus.The study also found that the poincare vortex is embedded with vector beams in the process of transmission, the rotation of the light intensity presents significant features. Direction of rotation, which is decided by the topological charge of plus or minus the topological charge is negative,it is into a clockwise.We can adjust the parameters at different conditions, the vortex beam will give a more ideal transmission effect.Compared with the traditional laser signal transmission in the atmosphere, the using of the vortex beam has great advantages.In this article,we analysis the results which explore the application of vortex beam in laser space technology has important theoretic and application value, the optical vortex in the atmospheric turbulence channel experimental study has important reference value. Studying the characteristics of vortex beam transmitting in the atmospheric turbulence has a great significance in laser radar, laser guidance, laser communication application field.