脉冲激光偏振方向对氧分子高次谐波的影响——基于含时密度泛函理论的模拟

Effect of laser polarization direction on high order harmonic generation of oxygen 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,模拟了氧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氧分子高次谐波的影响.结果表明氧分子的高次谐波谱具有典型原子谐波谱的特征;当θ=45°(激光偏振方向与分子轴向夹角)时,谐波谱强度最大.这与文献报道的实验结果基本一致.

The high order harmonic generation （HHG） of 02 radiated by ultra-strong femto-second pulsed laser beam is simulated by the time dependent density functional theory （TDDFT） method with the general gradient approximation （GGA） of the exchange-correlation energy. The effect of different laser polarization directions on HHG is discussed. The results indicate that the HHG spectrum of O2 has the similar characteristic as the typical atom HHG spectrum. The HHG yields peaks when the molecules are aligned at about 45° from the polarization axis. Good agreements are found with the experiment.