Measurement of CO2laser atmospheric transmission property based on Mie scattering
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摘要:为了更准确地计算大气透过率,在Mie散射理论基础上,分析了雷达系统设计中需考虑的大气透过率的经验计算公式,指出了该经验公式的不足。考虑大气分析软件MODTRAN自身的优点,采用经验公式和软件计算相结合的方式计算大气透过率,给出了MODTRAN计算结果的修正表达式。在该理论指导下,进行了CO2 大气传输实验。由于没有考虑大气湍流,理论计算和实验结果存在一定偏差,但不影响本文方法的实用性。实验测量显示, 器出口处光斑能量抖动比为6.18%,而在50 m和1 km处能量抖动比分别为8.3%和50.2%,表明随着传输距离增加,能量抖动比增大。除掉 器本身输出能量抖动外,在50 m和1 km处由大气传输造成的能量抖动比分别为2.12%和44.02%。实验结果提示,水平传输1 km时能量抖动已相当剧烈,所以对更远距离的 传输,自适应光学补偿显得尤为重要。Abstract:In order to calculate the atmospheric transmittance more correctly, the empirical expression of atmosphere transmittance which should be considered in the design of lidar systems based on Mie theory was analyzed in this paper, and the disadvantage of the empirical expression was demonstrated. In consideration of the merits both the empirical expression and MODTRAN software, they were combined to calculate the atmospheric transmittance. As a result, a modified transmittance expression was achieved. The atmospheric transmittance experiments of CO2 laser were completed under the theory above. The actual results and the theory have some differences without considering the atmosphere turbulence, but there is no impact on the practicability of the theory. The experimental results show that the energy drift ratio of the laser is 6.18% at the output window, and 8.3% and 50.2% at the distances of 50 m and 1000 m, respectively, which means the ratios increase with the enlargement of distance. The main reason of the drift is the atmospheric transmission according to the experimental environments. Excluding the drift ratios at the output window of the CO2 laser, the energy drift ratios are 2.12% and 44.02% at 50 m and 1 000 m, respectively. The experimental results demonstrate that the energy twitter has been so fiercely at 1 000 m, therefore, the adaptive optics compensation is very important in the long-range atmospheric transmission.
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[1] 阴俊燕,尹福昌,陈明,等. 影响 大气传输因素分析 [J]. 红外与 工程 ,2008,37:399-402. YIN J Y,YIN F CH,CHEN M,et al.. Impact on laser transmission in atmosphere [J].Infrared and Laser Eng., 2008,37:399-402.(in Chinese) [2] 于继平,齐文宗,郭春凤,等. 大气传输特性的数值模拟 [J]. 与红外 ,2008 ,38(6):523-527. YU J P,QI W Z,GUO CH F,et al.. Numerical simulation of laser propagation through atmospheric turbulence [J].Laser&Infrared,2008,38(6):523-527.(in Chinese) [3] 庞春颖,张涛. 主动成像系统信噪比模型的研究 [J]. 光学 精密工程 ,2008,16(2):615-621. PANG CH Y,ZHANG T. Signal-to-noise ratio model of laser active imaging system [J].Opt. Precision Eng.,2008,16(2):615-621.(in Chinese) [4] MCDONALD T E. Range-gated imaging experiment s using gated intensifiers [J].SPIE,1999,3642:142-148. [5] DAVID D,STEVE B. Long-range laser illuminated imaging:analysis and experimental demonstrations [J].Opt. Eng.,2001,40(6):1001-1009. [6] 王智,贾书洪,张晓辉,等. 主动成像图像的多帧后处理算法研究 [J]. 光学 精密工程 ,2007,15(4):615-621. WANG ZH,JIA SH H,ZHANG X H,et al.. Multiframe postprocessing algorithm of laser active imaging images [J].Opt. Precision Eng.,2007,15(4):615-621.(in English) [7] COOKE C R. Automatic laser tracking and ranging system [J].Appl. Opt.,1972,11(2):277-284. [8] 袁纵横,张静,张文涛,等. 基于大气湍流效应的双波长 传输特性实验研究 [J]. 光学技术 ,2009,35(5):686-690. YUAN Z H,ZHANG J,ZHANG W T,et al.. Experimental study on transmission characteristics of dual wavelength laser in atmospheric turbulence [J].Opt. Technique,2009,35(5):686-690.(in Chinese) [9] 柯熙政,马冬冬,刘佳妮. 在雾中传输的衰减研究 [J]. 光散射学报 ,2009,21(2):104-109. KE X ZH,MA D D,LIU J N. Study attenuation of laser transmission in fog [J].Chinese J. Light Scattering,2009,21(2):104-109.(in Chinese) [10] 袁易君,任德明,胡孝勇. Mie理论递推计算散射相位函数 [J]. 光散射学报 ,2006,17(4):366-371. YUAN Y J,REN D M,HU X Y. Computing scattering phase function by recursive formula of Mie theory [J].Chinese J. Light Scattering,2006,17(4):366-371.(in Chinese) [11] FU Q,SUN W B. Mie theory for light scattering by a spherical particle in an absorbing medium [J].Appl. Opt.,2001,40 (9):1353-1361. [12] WICOMBE W J . Improved Mie scattering algorithms [J].Appl. Opt.,1980,19:1505-1509. [13] 戴永江. 雷达原理 [M]. 北京:国防工业出版社,2001. DAI Y J.The Principle of Lidar[M]. Beijing:National Defence Industry Press,2001.(in Chinese) [14] 吴健,杨春平,刘建斌,等.大气中的光传输理论 [M]. 北京:北京邮电大学出版社,2006. WU J,YANG CH P,LIU J B,et al.. Optical Transmission Theory in the Atmosphere[M]. Beijing:Beijing University of Posts and Telecommunications Press,2006.(in Chinese)
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