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The analytical expression for the root-mean-square (Rms) beam width of the radial Gaussian beam array propagating in oceanic turbulence is derived, where the coherent combination is considered. Meanwhile, the analytical expression for effect of the turbulence on the beam F is also obtained. Giving a comparison of results of F calculated by the analytical expression and the previously integrating one, it can be seen that the two results are in agreement with each other exactly. Further, the influences of the rate of dissipation of mean-squared temperatureχ(T), the rate of dissipation of kinetic energy per unit mass of seawater εand the ratio of temperature to salinity contribution to the refractive index spectrum w are investigated. The results indicate that the Rms beam width increases as χ(T) increases, εdecreases and the salinity-induced turbulence dominates. Moreover, the changings of effective radius of curvature with mentioned above parameters are studied. The strength of turbulence determines the value of effective radius of curvature, and which decreases asχ(T) and w increases, and εdecreases.

Recent work has indicated that ghost imaging might find useful application in standoff sensing where atmospheric turbulence is a serious problem. There has been theoretical study of ghost imaging in the presence of turbulence. However, most work has addressed signal-wavelength ghost imaging. Two-wavelength ghost imaging through atmospheric turbulence is theoretically studied in this paper. Based on the extended Huygens-Fresnel integral, the analytical expressions describing atmospheric turbulence effects on the point spread function (PSF) and field of view (FOV) are derived. The computational case is also reported.

We demonstrate for the first time (to our knowledge) that a high-quality image can still be obtained in atmospheric turbulence by applying adaptive optical ghost imaging (AOGI) system even when conventional ghost imaging system fails to produce an image. The performance of AOGI under different strength of atmospheric turbulence is investigated by simulation. The influence of adaptive optics system with different numbers of adaptive mirror elements on obtained image quality is also studied.

The influence mechanism of higher-order Kerr effect on the propagation of laser beam is investigated by a modified model, which indicates that a collapsing wave will transform into a universe blowup profile. The analysis of higher-order terms of the nonlinear refractive index shows that the filamentation process can be induced by Kerr self-focusing without the occurrence of the ionization effect. The determining role of the combination of self-focusing and spontaneous defocusing and the energy reservoir in formation of lengthy filament is confirmed visually.

High-order laser guide star performance for the Euro50 telescope is analyzed. Focus anisoplanatism residual errors using multiple LGSs are obtained by numerical simulations. Results calculated for annual mean conditions at the La Palma site show that, considering only focus anisoplanatism, it will be possible to obtain a Strehl ratio of 0.72~0.82 at 2.2 microm using 13 LGSs. A Strehl ratio of 0.60~0.70 can be obtained at 1.25 microm using 21 LGSs. The dependence of wavefront measurement error on pulsed laser power is also investigated. The variance of the measurement error is lower than 0.2 rad2 when the laser power is larger than 14 W.