Terasaka Kenichiro, Yoshimura Shinji, Minagawa Hiroki, Aramaki Mitsutoshi
Interdisciplinary Graduate School of Engineering Sciences, Kushu University, Kasuga, Fukuoka, 816-8580, Japan.
Department of Computer and Information Sciences, Sojo University, Kumamoto, Kumamoto, 860-0082, Japan.
Sci Rep. 2024 Jan 23;14(1):2005. doi: 10.1038/s41598-024-52179-0.
Laser-induced fluorescence (LIF) Doppler spectroscopy using an optical vortex beam with an asymmetric intensity distribution, referred to as aOVLIF, is proposed as a new method to measure plasma flow velocity. LIF spectra were calculated numerically using typical laboratory low-temperature plasma parameters, and it was revealed that an ion flow across the beam produces a frequency shift of the spectra. This method also has the capability of temperature measurements. The propagation effects of asymmetric optical vortex beams are discussed assuming an actual experiment, and it is found that the sensitivity to the transverse flow velocity is approximately unchanged. The aOVLIF method, which exploits the inhomogeneous phase structure of optical vortices, can be applied to the determination of three-dimensional velocity vectors and promises to enhance the usefulness of conventional LIF spectroscopy using plane waves.
提出了一种利用具有非对称强度分布的光学涡旋光束的激光诱导荧光（LIF）多普勒光谱技术，即非对称光学涡旋激光诱导荧光（aOVLIF），作为一种测量等离子体流速的新方法。利用典型的实验室低温等离子体参数对LIF光谱进行了数值计算，结果表明，离子束流会使光谱产生频移。该方法还具备温度测量能力。假设进行实际实验，讨论了非对称光学涡旋光束的传播效应，发现其对横向流速的灵敏度大致不变。aOVLIF方法利用了光学涡旋的非均匀相位结构，可用于确定三维速度矢量，并有望提高使用平面波的传统LIF光谱的实用性。
