采用分步法结合Hankel变换对修正薛定谔方程进行数值求解,通过数值计算对飞秒脉冲在非线性正色散介质中的自聚焦特性进行了简要分析.在此基础上,针对啁啾脉冲放大系统(CPA)中的啁啾高斯脉冲,对其全光束自聚焦特性进行了计算模拟和分析讨论.研究结果表明,群速度色散(GVD)对大啁啾脉冲的影响很小,谱宽对自聚集的影响可以忽略.因此,具有大啁啾的脉冲在非线性正色散介质中的自聚焦特性不同于飞秒脉冲,而与纳秒脉冲相似.

The self-focusing properties of the femtosecond pulse were analyzed through numerical calculation using modified Schrdinger equation.On the basis of the analysis,the self-focusing properties of the chirped Gaussian pulse in the chirped pulse amplification(CPA) system were analyzed and discussed,and the numerical calculations were performed.The results showed that the effect of group velocity dispersion(GVD) on the pulse with large chip was slight and the effect of spectral width on the self-focusing properties could be ignored.Consequently,the self-focusing properties of the pulse with large chirp in the nonlinear medium with normal dispersion were different from those of femtosecond pulse,but similar to those of nanosecond pulse.