激光技术, 2010, 34 (4): 542, 网络出版: 2010-09-25
部分相干平顶光束序列在湍流大气中传输特性
Propagation properties of partially coherent flat-topped beam array in a turbulent atmosphere
大气与海洋光学 扩展的惠更斯-菲涅耳原理 部分相干平顶光束序列 传输 atmospheric and ocean optics extend Huygens-Fresnel integral partially coherent flat-topped beam array propagation
摘要
为了研究部分相干平顶光束序列在湍流中的传输特性,采用扩展Huygens-Fresnel 原理,得到了相应的解析表达式,并运用MATHEMATICA进行了相应的数值模拟。结果表明,湍流一定时,相干长度越小,变成高斯光束的趋势越快;光束阶数越大、相干长度越小,部分相干平顶光束序列的相对束腰宽度扩散较快;相干长度越小、光束阶数越大,部分相干平顶光束序列的斯特列尔比受湍流影响越小;在远场中,当阶数改变,桶半宽度小于4倍光束的束腰宽度时,平顶光束序列的光束阶数相对高,桶中功率相对大,桶半宽度大于4倍光束的束腰宽度时,平顶光束序列的光束阶数相对高,桶中功率相对小;当光束的相干长度改变时,桶半宽度小于4倍光束的束腰宽度时,平顶光束序列的相干长度σ越小,桶中功率越大,桶半宽度大于4倍光束的束腰宽度时,相干长度σ越大,桶中功率越大。这些结果对激光在通信方面具有一定的实际应用。
Abstract
In order to study propagation properties of partially coherent flat-topped (PCFT) beam array in a turbulent atmosphere, corresponding analytical formulate were derived based on the extend Huygens-Fresnel integral and numerical simulation was carried out with MATHEMATICA. The results indicate that for certain turbulence, the smaller coherence length, the faster it becomes Gaussian beam. The influence of atmospheric turbulence on the relative beam width spreading is larger for PCFT beam array with larger beam order and smaller coherence length. The strehl ratio of PCFT beam array with smaller coherence length and bigger beam order are less affected by turbulence.In the far field, for different beam order, if the bucket radius is four times smaller than the waist width of beams, the power in the bucket(PIB)is larger for PCFT beam array with the higher beam order. However, if the bucket radius is four times larger than the waist width of beams, its PIB is smaller. For different coherence length, when the bucket radius is four times smaller than the waist width of beams, the PIB is larger for PCFT beam array with the smaller coherence length, but its PIB is smaller when the bucket radius is four times larger than the waist width of beams. These results are useful for laser communication application.
钟燕丽, 崔执凤, 石建平, 屈军. 部分相干平顶光束序列在湍流大气中传输特性[J]. 激光技术, 2010, 34(4): 542. ZHONG Yan-li, CUI Zhi-feng, SHI Jian-ping, QU Jun. Propagation properties of partially coherent flat-topped beam array in a turbulent atmosphere[J]. Laser Technology, 2010, 34(4): 542.