|
Owing to the enhancement effect of backscattering for laser propagation through turbulent atmosphere, a comparison between theoretical analysis and model simulation based on random phase screen is conducted, and then a preliminary experiment observation is carried out for the enhanced backscattering effect for laser propagation in turbulence atmospheric. Firstly, from the generalized Huygens-Fresnel principle and the mutual interference effect, the light intensity expression and the backscattering enhancement coefficient are derived for the backscattering enhancement effect of laser propagation through turbulence atmospheric to the reflecting screen. The backscattering enhancement coefficient based on theoretical analysis increases as laser transmission distance increases, whereas it decreases to 1 with the increase of the distance between receiver and transmitter. Furthermore, random phase screens are respectively established for turbulence through the power spectrum inversion method, Zernike polynomial method and low-high frequency combination method and are compared with the theoretical values. Then the laser propagation through turbulent atmosphere is simulated to verify that the laser propagation through turbulence atmospheric possesses backscattering enhancement effect, and the influence of the factors on the backscattering enhancement effect is analyzed. Simulations show that there is a saturation effect of the enhanced backscattering, and its value is approximately 1.4. While the atmospheric refractive index structure constant is 10 -13, the enhanced backscattering effect gradually reach saturation at the laser propagating to 600m. Whereas the enhanced backscattering effect gradually reach saturation with the atmospheric refractive index structure constant of 10 -14 at the distance of 1500m. The enhanced backscattering effect of laser propagation through turbulent atmosphere is preliminarily observed through an experimental system. The results show that the backscattering enhancement effect is positively correlated with the change of the wind speed in the area where the laser passes through, decreases as the temperature drop, and increases with the increase of the laser propagating distance, and that the backscattering enhancement coefficient is less than 1.4.
|
