Wander Of Partially Coherent Beam Through Atmospheric Turbulence

The intensity of laser beam during the transmission of communication link would be weakened by the turbulent atmosphere and the beam will be expanded. Therefore, it was necessary to research transmission characteristics of beam in turbulent atmosphere. This research mainly investigated the partially coherent Gaussian-Schell pulse beams respectively along the horizontal and inclined in the atmospheric turbulence, when path transmission beam was expanded in time domain and frequency domain. Main works are as follows:1. According to the generalized Huygens-Fresnel principle and the modified von Karman spectrum model, the beam radius expansion of partially coherent GSMP beams in atmospheric turbulence was analyzed.2. The formula of average beam intensity was deduced, and the beam expansion problem of GSMP beam under different coherence length was analyzed, and this research discussed the change of GSMP beam along the horizontal and slant path transmission beam radius affected by the turbulence, and the corresponding analysis was presented.3. The formula of beam radius for partially coherent GSMP beam in the atmospheric turbulence in frequency domain and time domain was given. The pulse broadening characteristics of partially coherent GSMP beams under different turbulence intensities was discussed.The results show: In the frequency domain, the radius of the GSMP beam would be expanded as the turbulence intensity and the outer scale increasing. In the time domain, the pulse width was smaller under the weak turbulence intensity; In the intensity of turbulence, the pulse width was increased rapidly and obviously. When the initial pulse width was constant, the higher the launch height, the faster the pulse width at the receiving end. The relative pulse width of the receiver decreased rapidly with the increase of initial pulse width, which was the increase of the receiver's pulse width as the initial pulse width increasing. When the zenith angle was ?? ?/2, the beam was a horizontal transmission, and pulse width increased faster at the receiving end, in addition, the spread of horizontal pulse was more obviously than that of oblique transmission.