Optical Charge Measurement at Nanoparticles in a Plasma

在这个项目中，我们将开发一种新颖的纯光学技术来解决气态尘埃等离子体中纳米（亚微米）粒子的充电问题。粒子的充电行为是这些等离子体的中心和基本方面。为此，我们将建立一个光学诊断，以测量粒子的电荷依赖的声子共振在红外（IR）光谱区的位移。我们将利用材料的光学声子共振随着尘埃表面上的电荷向更高能量（更短波长）移动。将针对不同的颗粒材料、颗粒尺寸和颗粒特性（例如具有正和负电子亲和力的材料）以及不同的等离子体参数测量声子共振的电荷依赖性位移。这使得在等离子体中的粒子的充电动力学和等离子体-粒子相互作用的基本和重要的属性的分析。原则上，这些结果可以转移到等离子体技术应用和具有纳米颗粒的天体物理等离子体中。

In this project we will develop a novel, pure optical technique to address the charging ofnanometric (submicron) particles in a gaseous dusty plasma. The charging behavior of particles is a central and fundamental aspect of these plasmas. For this purpose, we will set up an optical diagnostic to measure the particle charge from the charge-dependent shift of phonon resonances in the infrared (IR) spectral regime. We will exploit that the optical phonon resonance of materials shifts with the charge on the dust surface towards higher energy (shorter wavelengths). The charge-dependent shift of the phonon resonance will be measured for different particle materials, particle sizes and particle properties, such as materials with positive and negative electron affinity, as well as for different plasma parameters. This allows the analysis of the charging dynamics of particles in a plasma and the fundamental and important properties of the plasma-particle interaction. The results can, in principle, be transferred to plasma-technological applications and astrophysical plasmas with nanoparticles.