将稳态场的相干偏振统一理论应用于脉冲光束的研究。构建了部分相干方形平顶电磁脉冲光束，并推导出该光束经相位调制透镜后聚焦的交叉谱密度函数表达式。详细探讨了相位调制尺寸、调制深度、调制中心位置以及光束相关长度等对聚焦场光谱强度的影响。研究结果表明，局域相位调制会导致在聚焦场中产生另一光谱强度峰值，光束的相关参数和相位调制参数决定该光谱强度峰值大小，并在一定情况下使之发生移动。特别是当光源相关参数和相位调制参数处于某临界值时，会发生光谱强度峰值开关现象。同时发现，空间相关长度导致光束发生空间焦移，而脉冲时间相关长度导致光谱强度峰值在频率上的移动。

Unified theory of coherence and polarization of stationary beams is applied to pulsed light beams research. Partially coherent square flat-topped electromagnetic pulsed beams have been constructed, and analytical expressions for cross-spectral density matrix of a class of the pulsed light beams focused by a phase modulated lens have been derived. A detailed study on effects of phase distortion radii, phase distortion depth, phase modulated position and correlation length on spectral density in focused filed is carried on. It is shown that local phase modulation will produce another spectral density peak in the focused field, and correlation parameter of source and phase modulation parameters determine the value of intensity peak, and make it shift in some cases. Especially when parameters of correlation of the source are chosen to be some values, a focal switch phenomenon will occur. Change of spatial coherent length of the source produces the spatially focal shift and pulse time correlation length also produces spectral density peak shift on frequency.