Atmospheric and Oceanic Optics|33 Article(s)
Inversion Method for Turbulence Profile Based upon Multi-aperture Scintillation Sensor
Zhi-bo NI, Hong-hua HUANG, Yin-bo HUANG, Ke-e YUAN, and Rui-zhong RAO
Based on the theory of multi-aperture scintillation sensor,the contribution of aperture filter function and spectral response function to weighting function are discussed,respectively.According to simulation results of scintillation with Hufnagel-Valley 5/7 model included bounding layer,vertical turbulence profile is inversed with the method of singular value decomposition.The magnitudes of the vertical inversion results are between and ,and decreases with height increased,which are all in accord with academic model.Using the measuring results of Shack-Hartman,horizontal turbulence profile is inversed,the transmission distance of which is 1 km.The magnitudes of horizontal inversion results are between 10-14 and 10-15,and the tendency accords the practice condition of experimental site depending on propagation distance,and accords the ensemble average depending on time.
Acta Photonica Sinica
  • Publication Date: Dec. 01, 2009
  • Vol. 38 Issue 12 3269 (2009)
Influence of Fog on Atmospheric Laser Communication System and the Relevant Methods
Yong WANG, Lei YU, Ya-bin ZHANG, and Jia-nian CAO
Acta Photonica Sinica
  • Publication Date: Dec. 01, 2009
  • Vol. 38 Issue 12 3275 (2009)
Density of Phase Branch Points for a Light Wave Propagation in Atmospheric Turbulence
Ke-e YUAN, Wen-yue ZHU, and Rui-zhong RAO
Under Rytov approximation and geometrical optics approximation, a formula of the variance of the log-amplitude derivative was deduced for the case of a plane wave propagating through turbulence. It was clarified that the main factors, which determined the variance, were the Rytov variance, the turbulence inner scale and the Fresnel size. And, based on the formulae deduced by Voitsekhovich, the expression for density of phase branch points was modified. The relationship between the density and the above mentioned parameters was analyzed thoroughly, which indicates that the density increases with Rytov variance increasing and decreases with turbulence inner scale and Fresnel size increasing under the condition of Rytov variance less than 1.
Acta Photonica Sinica
  • Publication Date: Feb. 01, 2009
  • Vol. 38 Issue 2 410 (2009)
Detection Performance of Heterodyne Lidar in Non-Kolmogorov Turbulence
Hua TANG, Wen-jing YANG, and Huan-yu LI
Based on Rytov approximation and extended Huygens-Fresnel principle, the analytical expressions for average intensity and scintillation index on target plane in non-Kolmogorov weak turbulence along slant paths were derived, the system efficiency of heterodyne lidar wass given. The system efficiency of heterodyne lidar is examined and the effects of exponent parameter, zenith angle, structure constant, system configurations and telescope aperture on system efficiency are also analyzed.It is shown that when the generalized index is less than 3.2 or greater than 3.8, the system efficiency decreases fast as the index increases. System efficiency decreases with the increase of zenith angle. System efficiency of bistatic configurations is smaller than that of monostatic configurations. With the increase of the telescope aperture, the system efficiency arrives the minimum, and eventually flattens out. In near field, the system efficiency of collimated beam is larger than the other two forms, but in far field the system efficiency of divergent beam is the largestone.
Acta Photonica Sinica
  • Publication Date: Feb. 01, 2015
  • Vol. 44 Issue 2 201001 (2015)
Intensity Distribution of Focused Hollow Vortex Beams with a Gaussian Background in Turbulent Atmosphere
Ji CANG, Yi-xin ZHANG, and JIAN-cai XU
Based on the extended Huygens-Fresnel principle and the quadratic approximation of phase structure function, the theoretical modal of optical intensity distribution on the focal plane for focused hollow vortex beams with a Gaussian background propagating in turbulent atmosphere was investigated and obtained.The effects of atmospheric index structure constant C2n, topological charge, focal length and beam wavelength on optical intensity distribution on the focal plane were analyzed. The results indicate that with the increase of focal length, the intensity distribution on the focal plane varies from central-dip form to Gaussian distribution. The effects of weak turbulence on intensity distribution are negligible. The maintenance of singularity of vortex beams with larger topological charge in turbulent atmosphere is better than that for vortex beams with smaller topological charge. The central-dip form of the intensity distribution becomes shallow and the intensity distribution becomes smooth with the turbulence outer scale increasing.
Acta Photonica Sinica
  • Publication Date: Aug. 01, 2009
  • Vol. 38 Issue 8 2122 (2009)
Research of Numerical Simulation and Comparison of Experiment from Differential Image Motion Monitor
Hua-lin CHEN, Chong PEI, Xiang-yan YUAN, and Xiang-qun CUI
Differential image motion monitor is widely used to obtain real-time seeing. Differential image motion was numerical simulated by random phase screen and optical defocus aberration, and the measurement accuracy of differential image motion monitor was analyzed, which showed that differential image motion monitor can reliably measure the near-ground turbulence. Comparision of experiment of two differential image motion monitors with the same hardwares was carried out at Xinglong Station of National Astronomical Observatory of China. The correlation between exposure time and measuring results was analyzed. The results show that the limited exposue time will reduce differential image motion and underestimate seeing value, and the trends over time and statistics of measurement results have good consistency.
Acta Photonica Sinica
  • Publication Date: Dec. 01, 2014
  • Vol. 43 Issue 12 1201001 (2014)