Mobile emission-based microspectrometer for the analysis of unknown gaseous substances

计划中的项目旨在研究一种新型的、高度小型化和移动式的未知气体和气体混合物光谱仪。与以前已知的气体光谱仪概念不同，该项目主要利用不同气体组分与红外光之间的吸收相互作用，所要研究的原理是基于未知气体混合物在等离子体中的电离，并同时对等离子体发射进行光谱评估。由于低压等离子体不适合移动设备，因为无法将泵系统小型化以产生真空，因此拟议的项目依赖于在大气压范围内使用微等离子体源，该源将采用紧凑型裂环谐振器(SRR)的形式。这种等离子体源以微波激励方式运行，因此点火和稳定放电的操作通常需要较大的激励功率，这严重地使其在移动设备中的使用复杂化。因此，计划中的项目将非常集中于减少等离子体源的能源需求，除其他外，将通过使用更高的激励频率、利用SRR的更高阶谐振频率和集成点火支持来实现这一目标。大气压下的操作和小的几何尺寸阻碍了待分析气体快速引入等离子体源。因此，拟议的项目将致力于一种改进的微泵，该微泵使用直接集成到移动结构中的流体通道。由于这些泵只能泵出非常少量的气体，因此还将研究表征它们的新方法。最后，必须对等离子体源的光发射进行光谱分割和测量。为此，拟议的项目将探索一种新的基于MEMS的微光谱仪，用于可见光范围，完全在平面内操作，并可以使用静电执行器进行调谐。此外，还将设计合适的薄膜探测器，并与光谱仪相结合。MEMS光谱仪本身已经是一个新事物，它与微等离子体源结合到芯片实验室进行光谱分析还没有被研究过。在项目结束时，将实现一个功能演示器，它将使用移动能源操作，完全采用硅技术。该演示器最终将允许研究流体动力学、等离子体物理和光谱光学效应及其相互作用，这最终决定了气体光谱仪的动力学、带宽、分辨率和重复性。

The planned project addresses the investigation of a novel, highly miniaturized and mobile spectrometer for unknown gases and gas mixtures. In contrast to the previously known concepts for gas spectrometers, which mainly use the absorption interaction between different gas components and light in the infrared range, the principle to be investigated in the project is based on the ionization of the unknown gas mixture in a plasma with simultaneous spectroscopic evaluation of the plasma emission. Since low-pressure plasmas are not suitable for mobile devices due to the inability to miniaturize pump systems for vacuum generation, the proposed project relies on the use of a microplasma source for the atmospheric pressure range, which will take the form of a compact split-ring resonator (SRR). Such plasma sources operate with microwave excitation, whereby large excitation powers are often required for ignition and operation of a stable discharge, which seriously complicates their use in mobile devices. The planned project will therefore focus very intensively on reducing the energy requirements of the plasma source, which will be achieved by, among other things, using higher excitation frequencies, utilizing higher-order resonance frequencies of the SRR, and an integrated ignition support. The operation under atmospheric pressure and the small geometrical dimensions hamper the rapid introduction of the gas to be analyzed into the plasma source. Therefore, the proposed project will work on an improved micropump that uses fluidic channels directly integrated into a moving structure. Since these pumps can only pump very small amounts of gas, new approaches to their characterization will also be investigated. Finally, the light emission of the plasma source has to be spectrally split and measured. To this end, the proposed project will explore a new MEMS-based microspectrometer for the VIS range that operates fully in-plane and can be tuned using electrostatic actuators. In addition, a suitable thin film detector will be designed and combined with the spectrometer. The MEMS spectrometer itself is already a novelty, its combination with a microplasma source to a lab-on-chip for spectral gas analysis has not been investigated yet.At the end of the project, a functional demonstrator is to be realized, which will be operated with a mobile energy source and built entirely in silicon technology. This demonstrator will finally allow the investigation of fluid dynamic, plasma physical and spectral optical effects as well as their interaction, which finally determines the dynamics, bandwidth, resolution and reproducibility of the gas spectrometer.