Pump-probe spectroscopy study of ultrafast temperature dynamics in nanoporous gold
Pump-probe spectroscopy study of ultrafast temperature dynamics in nanoporous gold
复制标题
DOI：
10.1103/physrevb.99.035435
复制
发表时间：
2019-01
影响因子：
3.7
通讯作者：
M. Ortolani;A. Mancini;A. Budweg;D. Garoli;D. Brida;F. Angelis
中科院分区：
文献类型：
--
作者：
M. Ortolani;A. Mancini;A. Budweg;D. Garoli;D. Brida;F. Angelis
我们探讨了纳米多孔结构对超短激光脉冲（$\sim 7$ fs）激发的金薄膜中电子和空穴热弛豫的影响。等离子体子衰变成热电子空穴对导致费米-狄拉克分布的产生，在高于晶格温度T_{l}}$的温度T_{e}$热化。电子和晶格之间的能量交换的弛豫时间，在这里测量的泵浦-探测光谱，被减慢的纳米多孔结构，导致更高的峰值T_{\mathrm{e}}$比散装金膜。的电子-声子耦合常数和德拜温度被发现与金属填充因子$f$和两个温度模型再现的数据。这一结果为通过纳米孔几何结构的工程化来控制金属中的电子温度开辟了道路。
We explore the influence of the nanoporous structure on the thermal relaxation of electrons and holes excited by ultrashort laser pulses ($\sim 7$ fs) in thin gold films. Plasmon decay into hot electron-hole pairs results in the generation of a Fermi-Dirac distribution thermalized at a temperature $T_{\mathrm{e}}$ higher than the lattice temperature $T_{\mathrm{l}}$. The relaxation times of the energy exchange between electrons and lattice, here measured by pump-probe spectroscopy, is slowed down by the nanoporous structure, resulting in much higher peak $T_{\mathrm{e}}$ than for bulk gold films. The electron-phonon coupling constant and the Debye temperature are found to scale with the metal filling factor $f$ and a two-temperature model reproduces the data. The results open the way for electron temperature control in metals by engineering of the nanoporous geometry.