标题： 通过可调谐二极管激光吸收光谱法在大气压射频等离子体喷流中对氦亚稳态密度进行二维空间分辨测量 显示英文标题

标题： Two-dimensional spatially resolved measurements of helium metastable densities by tunable diode laser absorption spectroscopy in atmospheric pressure RF plasma jets

摘要： 氦亚稳态粒子在通过Penning电离维持射频(RF)驱动的微大气压等离子体喷流以及生成活性氧和氮物种(RONS)中起着关键作用。它们的密度通常使用可调谐二极管激光吸收光谱(TDLAS)进行测量。大多数空间分辨的TDLAS方法依赖于窄激光束在等离子体上的机械扫描，这耗时且限制了空间分辨率。在本工作中，我们提出了一种先进的二维(2D) TDLAS方法，能够在不需要机械扫描的情况下直接对氦亚稳态密度进行空间映射。采用旋转光学扩散器来抑制斑点干扰并在等离子体区域产生均匀照明。使用配备远心镜头的短波长红外相机捕捉吸收谱图，在整个视场内实现了高空间分辨率(约10 {\mu }m)。这种方法显著提高了数据质量和采集速度。改进的二维TDLAS系统被用于测量由不同定制电压波形驱动的结构电极等离子体喷流中的氦亚稳态密度。结果与流体模拟和以前报道的实验数据有很好的定性一致性。 显示英文摘要

摘要： Helium metastable species play a critical role in sustaining radio-frequency (RF) driven micro atmospheric pressure plasma jets through Penning ionization and for the generation of reactive oxygen and nitrogen species (RONS). Their densities are typically measured using tunable diode laser absorption spectroscopy (TDLAS). Most spatially resolved TDLAS approaches rely on mechanical scanning of a narrow laser beam across the plasma, which is time-consuming and limits spatial resolution. In this work, we present an advanced two-dimensional (2D) TDLAS method that enables direct spatial mapping of helium metastable densities without the need for mechanical scanning. A rotating optical diffuser is employed to suppress speckle interference and generate uniform illumination across the plasma region. The absorption profile is captured using a short-wavelength infrared camera equipped with a telecentric lens, achieving high spatial resolution (approximately 10 {\mu}m) across the entire field of view. This approach significantly enhances both data quality and acquisition speed. The improved 2D TDLAS system is applied to measure helium metastable densities in plasma jets with structured electrodes driven by different tailored voltage waveforms. The results show very good qualitative agreement with fluid simulations and previously reported experimental data.