The effect of propagation of the laser beam on the atmospheric turbulence conditions

Atmospheric turbulence which have been the research subject for many years is one of the most critical parameters for systems based on laser. Due to differences in temperature, pressure and humidity, the laser beam propagating in turbulence medium encounters turbulence eddy with different refractive index and various disturbances might be observed. In this thesis, Gaussian laser beam exiting from the source is simulated using MATLAB. Then phase screens are modeled at certain distances through interval by applying a random phase screen model to create atmospheric turbulence medium. When phase screens are modeled, the spectrum model used is Non-Kolmogorov spectrum model. Within this model, the atmospheric inner and outer scale diameter is defined in terms of cm and m, respectively. The distorted beam is numerically computed by passing the generated phase screens through the media to simulate the propagation of Gaussian laser beam in atmospheric turbulence. In addition, when the laser beam with the same parameters is propagating in the vacuum medium, the spot diameter in the receiving plane is calculated. Thus, the laser beam spot diameter emitted in the turbulent atmosphere is compared with the spot diameter in the receiving plane. According to the model it is showed that as interval increases, the effect of the turbulence parameter on laser beam increases. The spot diameter at the source plane is showed how the atmospheric turbulence will affect to it. The larger the spot diameter in the transmitter plane, the less the effect of the turbulence parameter.