光子学报, 2019, 48 (10): 1001002, 网络出版: 2019-11-14
超连续谱激光在湍流大气中传输特性的数值仿真研究
Numerical Simulation of Propagation Performance of Super-continuum Laser in Turbulent Atmosphere
超连续谱激光传输 数值仿真 光斑漂移 光束扩展 大气湍流 光强闪烁指数 Super-continuum laser propagation Numerical simulation Beam wandering Beam spreading Atmospheric turbulence Intensity scintillation index
摘要
采用多层相位屏的数值仿真方法,综合考虑大气衰减效应和湍流效应,研究了不同湍流强度和不同源相干度条件下超连续谱激光的光束扩展、光斑漂移以及闪烁特性,并对比分析了超连续谱激光传输与单色激光传输特性的差异.结果表明:湍流越强或源相干度越好,超连续谱激光的相对光束扩展越严重;湍流愈强,光斑漂移愈严重,但不同源相干度的超连续谱激光的质心漂移方差几乎相等;降低超连续谱激光的源相干度可以在一定程度上减弱光强起伏的闪烁效应,并降低闪烁指数对离轴距离的依赖性;与单色激光相比,湍流对超连续谱激光的光束扩展以及闪烁效应影响较弱,而质心漂移效应两者差异不明显.单色激光大气传输的数值仿真结果与理论解析结果基本吻合,在一定程度上说明了数值仿真过程的可靠性.该研究不仅提出了一种获得超连续谱激光大气传输特性规律的有效仿真手段,而且为超连续谱激光传输的工程应用提供参考.
Abstract
Considering the atmospheric extinction and turbulent effects, beam spreading, beam wandering and intensity scintillation of super-continuum laser propagating in atmospheric turbulence are studied by using multi-phase screen simulation method. And the difference of propagation properties between super-continuum laser and monochrome laser is analyzed. The simulation results show that, to super-continuum source, with the increase of turbulence strength or the increase of source coherence, relative beam spreading becomes more serious. As turbulence strength increases, beam wandering becomes more pronounced. And the RMS of beam wandering is insensitive to the variation of source coherent degree. Scintillation index and the dependence of scintillation index on off-axis distance may decline by reducing source coherence. Compared with the monochromatic laser, the relative beam spreading and intensity scintillation of super-continuum laser are less affected by turbulence, while the difference of beam wandering is not obvious. The agreement between results of numerical simulations and the theoretical analysis results of monochromatic laser propagating in atmospheric turbulence illustrated the reliability of the numerical simulation process. This study not only proposes an effective simulation method to obtain the atmospheric propagation characteristics of super-continuum laser, but also provides meaningful reference for the application of super-continuum laser.
李雅倩, 朱文越, 钱仙妹. 超连续谱激光在湍流大气中传输特性的数值仿真研究[J]. 光子学报, 2019, 48(10): 1001002. LI Ya-qian, ZHU Wen-yue, QIAN Xian-mei. Numerical Simulation of Propagation Performance of Super-continuum Laser in Turbulent Atmosphere[J]. ACTA PHOTONICA SINICA, 2019, 48(10): 1001002.