Measurement of the thermal wave in metal films using femtosecond laser thermoreflectance system
Measurement of the thermal wave in metal films using femtosecond laser thermoreflectance system
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使用飞秒激光热反射系统测量金属薄膜中的热波
DOI：
10.7498/aps.59.3856
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发表时间：
2010-06
期刊：
影响因子：
--
通讯作者：
Wang Wei
中科院分区：
文献类型：
--
作者：
Wang Haidong;Ma Weigang;Zhang Xing;Wang Wei
过去，人们用不同的实验方法研究了超快激光加热金属薄膜时产生的热波现象。在我们的实验中，我们使用飞秒激光泵浦-探测系统来研究电子和声子之间的超快能量传输。实验表明，在激光脉冲产生的主峰之后，电子温度曲线上出现了一个微弱的波峰。对于不同的激光强度和不同的薄膜样品，测试了结果的重复性。这种电子温度的弱峰可以用后表面热波的反射来解释。实验结果与双曲线两步模型计算的理论曲线相吻合。热波速度约为5×105m/S，电子弛豫时间约为60fs。
The thermal wave phenomenon induced by the ultrafast laser heating in metal films has been studied by different experimental methods in the past. In our experiment, a femtosecond laser pump-probe system is used to study the ultrafast energy transport between the electrons and phonons. The experiments showed a weak wave peak in the electron temperature curve following the main peak caused by the laser pulse. The reproducibility of the results has been tested for different laser intensities and different film samples. This weak peak in electron temperature could be explained by the reflection of the thermal wave from the rear surface. The experimental results agree with the theoretical curves calculated by the hyperbolic two-step model. The speed of the thermal wave is about 5×10 5 m/s and the electron relaxation time is about 60 fs.