部分空间相干和部分光谱相干厄米-高斯脉冲光束的焦场的相干特性

摘要

Based on the propagation law of partially coherent beams and Fourier transform, the analytical expressions for the spectral intensity and spectral degree of coherence of focused spatially and spectrally partially coherent Hermite-Gaussian (H-G) pulsed beams are derived and used to study the spatial correlation properties in the focal region. It is shown that the spectral degree of coherence depends on the spatial correlation length, temporal coherence length and beam order. As the temporal coherence length decreases, the spectral degree of coherence decreases, whereas the temporal coherence length does not contribute to the spatial distribution of the spectral degree of coherence. An increase of the beam order results in an oscillatory behavior of the spectral degree of coherence, which becomes more prominent with the increase of beam order or the decrease of spatial correlation length.%从部分相干光的传输理论出发，采用傅里叶变换法，推导出聚焦部分空间相干部分光谱相干厄米一高斯脉冲光束的光谱和光谱相干度的解析表达式，并用以研究了聚焦场的相干特性．研究结果表明，聚焦光束的光谱相干度与空间相关长度、时间相干长度和光束阶数有关．时间相干长度的减小将引起光谱相干度的减小，但光谱相干度的空间分布特性不受影响．随着光束阶数的增大，光谱相干度会出现振荡，且光束阶数越大，空间相关长度越小，振荡越明显．