采用结合双温模型的分子动力学的方法,数值模拟了脉宽100 fs,能量密度为40~200 m J/cm^2的飞秒激光与CuZr非晶合金的相互作用过程。低能量密度下,靶材的烧蚀机制主要表现为机械破碎;高能量密度下,热机械蚀除和相爆炸共同存在于靶材的烧蚀过程,随着能量密度的增加,相爆炸成为主要蚀除机制。利用径向分布函数分析了CuZr非晶合金结构的无序性,分析结果表明,激光能量密度由80 m J/cm^2增加到120 m J/cm^2时,飞秒激光与靶材相互作用过程中,材料内部的原子保持着无序状态,材料未发生明显晶化。
We theoretically investigate the Autler–Townes（AT） splitting in the photoelectron spectrum of four-level ladder K2 molecule driven by a pump 1-pump 2-probe pulse via employing the time-dependent wave packet approach. The effects of the pump-1 laser intensity and wavelength on AT splitting are studied for the first time. The magnitude of AT splitting increases with increasing the pump-1 laser intensity. The triple splitting with asymmetric profile occurs due to the nonresonant excitation. The triple structure is transformed into a double structure（near-resonant region）, and then becomes a peak（far-off resonant region） progressively as the pump-1 laser is detuned from the resonance wavelength, which can be explained in terms of the asymmetric excitation/population of dressed states. The splitting between adjacent peaks and the splitting between the two sideband peaks in the triplet do not change with the pump-1 pulse wavelength. The three peaks shift toward lower energy with the same shift 1/4^＊△1 as the pump-1 wavelength changes in near-resonant region.The asymptotic behaviors of AT splitting with the pump-1 laser intensity are interesting in the threshold points of the near-resonant region and the far-off resonant region.
