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Research on optical properties of warm dense matter using ultra-short-pulse lasers

超短脉冲激光研究热致密物质的光学性质

基本信息

批准号：
13480123
负责人：
YONEDA Hitoki
金额：
$ 9.47万
依托单位：
The University of Electro-Communications
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13480123/
关键词：
Ultra-short pulse laser high energy density matter warm dense matter Pump probe localization complex dielectric constant metal-insulator transition strongly coupled plasma 輪送過程フォノン緩和電子イオン衝突周波数

项目摘要

The purpose of this research is to explore properties of matter at novel conditions. Using ultra-short pulse lasers, we produce and study matter at high energy density, corresponding to temperatures of 1,000〜100,000 Kelvin. Although very high energy densities can be created by various laboratory technologies, the resulting pressure is too high to confine and the heated material expands rapidly. For this reason it is important to develop high-speed (dynamic) diagnostic techniques.Short-pulse laser pump-probe experiments can now be performed with high repetition rate and give a continuous time scan of target reflectivity changes during and after the heat pulse. The probe pulse duration provides a time resolution 100fsec. A single reflected probe pulse yields four signals, which characterize the elliptic polarization of the reflected light, a technique called "ellipsometry". We also have developed new computer tools to analyze or interpret the results.In the analysis of experiments on low … More -temperature gold plasmas, we found evidence for a strong reduction of free-electron electrical conductivity consistent with localization of electrons. Solutions of the Saha equation predict an anomalous plasma composition in which positive ions Au+ and negative ions Au- are balanced with very few free electrons. Evidence for anomalous low conductivity in low-temperature plasmas has emerged from other experimental techniques including direct measurement of DC conductivities in pulse-heated systems such as wire arrays, capillaries, etc. Under certain circumstances, quantum molecular-dynamic simulations also predict low conductivity.This work is not yet ready to discuss the details in the warm dense matter. Rather we are making a first quantitative exploration with the goal of identifying the main physical phenomena, especially as regards metal-insulator transitions, applicability of basic ideas of plasma EOS, Drude conductivity, etc.In near future, we will have a database of many atomic polarizabilities and dielectric functions for real materials, data qualified by comparison to experiments. Less

这项研究的目的是探索物质在新条件下的性质。使用超短脉冲激光，我们生产和研究高能量密度的物质，对应于1，000至100，000开尔文的温度。虽然各种实验室技术可以产生非常高的能量密度，但产生的压力太高而无法限制，并且加热的材料迅速膨胀。因此，发展高速（动态）诊断技术是很重要的。短脉冲激光泵浦探测实验现在可以以高重复率进行，并在热脉冲期间和之后对目标反射率的变化进行连续时间扫描。探测脉冲持续时间提供100 fsec的时间分辨率。单个反射探测脉冲会产生四个信号，这些信号表征反射光的椭圆偏振，这种技术称为“椭圆偏振法”。我们还开发了新的计算机工具来分析或解释结果。 ...更多信息 - 温度的金等离子体，我们发现了一个强大的自由电子电导率降低与本地化的电子一致的证据。Saha方程的解预测了异常的等离子体组成，其中正离子Au+和负离子Au-与非常少的自由电子平衡。低温等离子体中异常低电导率的证据已经出现在其他实验技术中，包括直接测量脉冲加热系统中的直流电导率，如导线阵列，毛细管等。在某些情况下，量子分子动力学模拟也预测低电导率。这项工作还没有准备好讨论温暖的致密物质的细节。相反，我们正在进行第一次定量探索的目标是确定主要的物理现象，特别是关于金属-绝缘体转换，适用性等离子体状态方程的基本思想，德鲁德电导率等，在不久的将来，我们将有一个数据库的许多原子极化率和介电函数的真实的材料，数据通过比较实验合格。少