斜程大气中聚焦J0相关部分相干光束的传输特性

采用部分相干光交叉谱密度理论，给出了适用于任意大气湍流条件的斜程湍流大气传输J₀相关部分相干光束在接收面内的长期平均光强分布、光束长期扩展和质量因子的解析表达式，分析了天顶角、传输距离、光源相干性以及湍流外尺度对接收面光强分布特性和光束扩展的影响.研究结果表明：在天顶角和传输距离一定的条件下，通过选择合适的光源相干性可控制焦面光强为平顶分布或中心光强为最大；在传输距离给定的条件下，随着天顶角或大气湍流外尺度的增加，焦斑光强分布均由中央凹陷分布逐渐变为高斯分布.焦面附近光强的中央凹陷比焦面的中央凹陷浅.J₀相关部分相干光束实际焦斑位置随天顶角、湍流外尺度的增加以及相干性减弱而移向发射端. 关键词： 部分相干束 大气湍流 0相关')" href="#">J₀相关 斜程传输

The propagation properties of J0-correlated partially coherent beams in the slant atmosphere

Based on the principle of cross spectral density of partially coherent beam，we have obtained the analytical expression of long term intensity distribution，long term beam width and quality factor on the receiver for J₀ correlated partially coherent beams propagating in the slant atmosphere，then analyzed the effects of zenith angle，propagation distance，coherence of source and turbulence outer scale on intensity distribution and beam width on the receiver. Results show that when the zenith angle and propagation distance are fixed，we can adjust the coherence of source to obtain the flattened optical intensity distribution or central maximum intensity value on the receiver. When the propagation is fixed，with the increase of zenith angle or the outer scale of turbulence，the intensity distribution varies from central dip to Gaussian distribution. Near the focal plane for short focal length，the central dip form of intensity distribution becomes deep first，then shallow with the propagation distance increasing. The real position of focal spot for J₀ correlated partially coherent beam moves toward the emitter with the increase of zenith angle and turbulence outer scale, or with the decrease of the source coherence.