近红外飞秒激光作用下金膜中的超快电子动力学

Ultrafast Electron Dynamics in Gold Films Probed by Near-infrared Femtosecond Laser

利用超快泵浦探测技术,研究了近红外飞秒强激光脉冲作用下,金膜中的超快电子动力学过程。研究发现,800 nm飞秒激光激发后,金膜的瞬态反射率存在一个下降过程。通过对金膜的瞬态反射率光谱进行分析和模拟,发现主要是自由电子弛豫和带间双光子跃迁这两种电子动力学过程综合作用的结果。利用双温模型,模拟了800 nm飞秒激光作用下金膜的温度弛豫和瞬态反射率变化过程,理论计算结果与实验结果符合良好。

Using ultrafast pump-probe technology,the ultrafast electron dynamics in gold films are investigated by near-infrared femtosecond laser.Transient reflectivity decrease after the 800 nm femtosecond laser excitation is observed.By analyzing and simulating the transient reflectivity spectrum difference,we found that it is mainly the result from the combined action of two kinds of electron dynamics:free electron relaxation and interband two-photon transitions.The two-temperature model is used to simulate the temperature relaxation and transient reflectivity difference,and the simulated results are in good agreement with the experimental results.