考虑到光束通过大气时受到大气湍流的影响,理论上分析了到达角起伏的原因,通过利用马尔科夫和平均强度的平方近似所求得到达角起伏公式,采用变形谱 Von Karman 所得出的波结构函数 D(ρ,z),得出到达角起伏在考虑湍流内外尺度和强度影响...考虑到光束通过大气时受到大气湍流的影响,理论上分析了到达角起伏的原因,通过利用马尔科夫和平均强度的平方近似所求得到达角起伏公式,采用变形谱 Von Karman 所得出的波结构函数 D(ρ,z),得出到达角起伏在考虑湍流内外尺度和强度影响下的到达角方差表达式.并在垂程方向上分析得出到达角方差随 L 增大而增大,在小于250 m 范围内,仅考虑湍流强度与考虑了湍流尺度和强度的影响相比,两者较接近,大于250 m 以后,考虑了湍流尺度和强度的影响比仅考虑湍流强度影响的大.展开更多
Under the quadratic approximation of the Rytov's phase structure function, this paper derives the general closed-form expressions for the mean-squared width and the angular spread of partially coherent beams in tu...Under the quadratic approximation of the Rytov's phase structure function, this paper derives the general closed-form expressions for the mean-squared width and the angular spread of partially coherent beams in turbulence. It finds that under a certain condition different types of partially coherent beams may have the same directionality as a fully coherent Gaussian beam in free space and also in atmospheric turbulence if the angular spread is chosen as the characteristic parameter of beam directionality. On the other hand, it shows that generally, the directionality of partially coherent beams expressed in terms of the angular spread is not consistent with that in terms of the normalized far-field average intensity distribution in free space, but the consistency can be achieved due to turbulence.展开更多
Based on a recently formulated unified theory of coherence and polarization, a method is described to study turbulence-induced changes in the polarization, the coherence and the spectrum of partially coherent electrom...Based on a recently formulated unified theory of coherence and polarization, a method is described to study turbulence-induced changes in the polarization, the coherence and the spectrum of partially coherent electromagnetic beams on propagation. The electromagnetic Gaussian Schell-model beam is taken as a typical example of partially coherent electromagnetic beams, and the closed-form expressions for the degree of polarization, the degree of coherence and the spectrum of electromagnetic Gaussian Schell-model beams propagating through atmospheric turbulence are derived in the quadratic approximation of Rytov's phase structure function. Some interesting results are obtained, which are illustrated by numerical examples and are explained in physics.展开更多
O43 2000042996低阶模式校正自适应光学系统的补偿效果分析=Analysis of compensation effectiveness for adaptive optical systems used as low-ordermodes correction[刊,中]/饶长辉,姜文汉,凌宁(中科院光电技术研究所.四川,成都(6...O43 2000042996低阶模式校正自适应光学系统的补偿效果分析=Analysis of compensation effectiveness for adaptive optical systems used as low-ordermodes correction[刊,中]/饶长辉,姜文汉,凌宁(中科院光电技术研究所.四川,成都(610209))//光学学报.-1999,19(12).-1615-1623引入规格化的相位谱,推导了大气湍流相位结构函数、低阶模式校正后的残余相位结构函数以及长曝光光学传递函数。分别给出了在各种不同大气湍流强度ρ<sub>0</sub>、展开更多
文摘考虑到光束通过大气时受到大气湍流的影响,理论上分析了到达角起伏的原因,通过利用马尔科夫和平均强度的平方近似所求得到达角起伏公式,采用变形谱 Von Karman 所得出的波结构函数 D(ρ,z),得出到达角起伏在考虑湍流内外尺度和强度影响下的到达角方差表达式.并在垂程方向上分析得出到达角方差随 L 增大而增大,在小于250 m 范围内,仅考虑湍流强度与考虑了湍流尺度和强度的影响相比,两者较接近,大于250 m 以后,考虑了湍流尺度和强度的影响比仅考虑湍流强度影响的大.
基金supported by the National Natural Science Foundation of China (Grant No. 60778048)
文摘Under the quadratic approximation of the Rytov's phase structure function, this paper derives the general closed-form expressions for the mean-squared width and the angular spread of partially coherent beams in turbulence. It finds that under a certain condition different types of partially coherent beams may have the same directionality as a fully coherent Gaussian beam in free space and also in atmospheric turbulence if the angular spread is chosen as the characteristic parameter of beam directionality. On the other hand, it shows that generally, the directionality of partially coherent beams expressed in terms of the angular spread is not consistent with that in terms of the normalized far-field average intensity distribution in free space, but the consistency can be achieved due to turbulence.
基金supported by the National Natural Science Foundation of China (Grant No. 60778048)
文摘Based on a recently formulated unified theory of coherence and polarization, a method is described to study turbulence-induced changes in the polarization, the coherence and the spectrum of partially coherent electromagnetic beams on propagation. The electromagnetic Gaussian Schell-model beam is taken as a typical example of partially coherent electromagnetic beams, and the closed-form expressions for the degree of polarization, the degree of coherence and the spectrum of electromagnetic Gaussian Schell-model beams propagating through atmospheric turbulence are derived in the quadratic approximation of Rytov's phase structure function. Some interesting results are obtained, which are illustrated by numerical examples and are explained in physics.
文摘O43 2000042996低阶模式校正自适应光学系统的补偿效果分析=Analysis of compensation effectiveness for adaptive optical systems used as low-ordermodes correction[刊,中]/饶长辉,姜文汉,凌宁(中科院光电技术研究所.四川,成都(610209))//光学学报.-1999,19(12).-1615-1623引入规格化的相位谱,推导了大气湍流相位结构函数、低阶模式校正后的残余相位结构函数以及长曝光光学传递函数。分别给出了在各种不同大气湍流强度ρ<sub>0</sub>、