Kim K Y, Yellampalle B, Glownia J H, Taylor A J, Rodriguez G
Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Phys Rev Lett. 2008 Apr 4;100(13):135002. doi: 10.1103/PhysRevLett.100.135002. Epub 2008 Apr 3.
We report the electrical conductivity of laser-produced warm dense aluminum plasmas measured using single-shot ultrafast terahertz (THz) frequency spectroscopy. In contrast with experiments performed at optical frequencies, measurements based upon THz probe reflectivity directly determine a quasi-dc electrical conductivity, and therefore the analysis does not require a free-electron Drude model based extrapolation to recover the near zero frequency conductivity. In fact, our experimental results indicate that the Drude model breaks down for warm (>0.6 eV), moderate-dense (<1.6 g/cm(3)) aluminum at THz frequencies. A calculation of THz reflectivity over a non-Fresnel boundary in dense plasmas is also presented.
我们报告了利用单次超快太赫兹（THz）频光谱测量激光产生的温稠密铝等离子体的电导率。与在光频下进行的实验不同，基于太赫兹探针反射率的测量直接确定了准直流电导率，因此该分析不需要基于自由电子德鲁德模型的外推来恢复接近零频率的电导率。事实上，我们的实验结果表明，在太赫兹频率下，德鲁德模型对于温（>0.6电子伏特）、中密（<1.6克/立方厘米）的铝失效。还给出了稠密等离子体中非菲涅耳边界上太赫兹反射率的计算结果。
