利用波长可调谐的强飞秒激光脉冲,在中红外波段系统地测量了氙原子的单电离离子产率随光强的变化关系。基于PPT模型和ADK模型进行了理论计算,并将理论计算结果与实验结果进行了对比,发现在整个测量区域,基于PPT模型的计算结果均与实验结果相符,而在较长波长、较高光强时基于ADK模型的计算结果与实验结果吻合较好。两种理论模型在深隧穿电离区域的一致性及其描述原子单电离行为的有效性在实验中得到了直接验证,可以利用这两种模型准确地标定长波长激光脉冲的绝对光强。

The variation relationship of ion yield for xenon atom under the single ionization in the mid-infrared band versus laser intensity is measured systematically by using the wavelength-tunable strong femtosecond laser pulses. The theoretical calculations based on the PPT and ADK models are done and the theoretical calculation results are compared with the experimental results. It is found that all the calculation results based on the ADK model are consistent with the experimental results in the whole measurement region, while the calculation results based on the ADK model do only when the wavelength is long enough and the intensity is strong enough. The unification for the two models in the deep tunneling ionization regime and the validity for the two models in describing the single ionization of atoms are directly verified in experiments, and thus these two models can be used as a precise tool to calibrate the absolute intensity of long wavelength laser pulses.