脉冲激光偏振方向对氮分子高次谐波的影响——基于含时密度泛函理论的模拟

Effect of different laser polarization direction on high order harmonic generation of nitrogen molecule——A simulation via TDDFT

采用含时密度泛函方法,结合赝势模型和电子交换相关作用的广义梯度近似,模拟了氮分子在超强飞秒激光脉冲作用下的高次谐波产生现象,并研究了激光脉冲偏振方向对氮分子高次谐波的影响.结果表明氮分子的高次谐波谱具有典型原子谐波谱的特征;谐波谱强度随着θ(激光偏振方向与分子轴向夹角)的增大而减小.这与J.Itatanl在Nature上报道的实验结果基本一致.

The high order harmonic generation （HHG） of nitrogen molecule irradiated by ultra-intense femto-second pulsed laser is simulated by the time dependent density functional theory （TDDFI＇） method with the general gradient approximation of the exchange-correlation energy. The effect of different laser polarization direction on HHG is discussed. The results indicate that the HHG spectrum of N2 has similar characteristics as the typical atom HHG spectrum. With the increase of the angle θ between laser polarization direction and molecular axis, the spectral intensity of HHG decreases, which is in agreement with the experimental result by J. hatanl published in Nature.