National Key Laboratory of Science and Technology on Tunable Laser, Institute of Opto-Electronics, Harbin Institute of Technology, Harbin, Heilongjiang, China.
J Xray Sci Technol. 2014;22(1):105-11. doi: 10.3233/XST-130412.
We experimentally study the harmonics from a Xe-He gas mixture using tight-focusing femtosecond laser pulses. The spectrum in the mixed gases exhibits an extended cutoff region from the harmonic H21 to H27. The potential explanation is that the harmonics photons from Xe contribute the electrons of He atoms to transmit into the excited-state. Therefore, the harmonics are emitted from He atoms easily. Furthermore, we show that there are the suppressed harmonics H15 and H17 in the mixed gases. The underlying mechanism is the destructive interference between harmonics generated from different atoms. Our results indicate that HHG from Xe-He gas mixture is an efficient method of obtaining the coherent soft X-ray source.
我们使用紧聚焦飞秒激光脉冲实验研究了 Xe-He 混合气体中的谐波。混合气体中的光谱在谐波 H21 到 H27 处表现出扩展的截止区域。可能的解释是，来自 Xe 的谐波光子将 He 原子的电子贡献到激发态中。因此，谐波很容易从 He 原子中发射出来。此外，我们表明在混合气体中存在被抑制的谐波 H15 和 H17。其潜在的机制是来自不同原子的谐波之间的相消干涉。我们的结果表明，Xe-He 气体混合物中的 HHG 是获得相干软 X 射线源的有效方法。
