Ionization effects on field-free molecular alignment observed with high-order harmonic generation

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• 作者：Xiaodong Guo ; Peng Liu ; Zhinan Zeng ; Pengfei Yu ; Ruxin Li ; Zhizhan Xu
• 刊名：Optics Communications
• 出版年：2009
• 出版时间：1 July 2009
• 年：2009
• 卷：282
• 期：13
• 页码：2539-2542
• 全文大小：533 K

文摘

In this paper, high-order harmonic generation (HHG) is demonstrated to provide a sensitive way for studying the dynamic process in the field-free molecular alignment. The dependence of the harmonic yield and the degree of alignment on the intensity of aligning pulse is observed in impulsively aligned CO₂ molecules. A good agreement is found between the experimental and calculated results. At low pump intensities, the harmonic yield increases monotonously until the ionization induced refractive index gradient and neutral molecule depletion are significant. The results show that the optimum intensity is around 8.95 × 10¹³ W/cm²; this value is related to the molecular ionization potential.