Doppler-shifted optical absorption characterization of plume-lateral expansion in laser ablation of a cerium target
Doppler-shifted optical absorption characterization of plume-lateral expansion in laser ablation of a cerium target
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DOI：
10.1063/1.4771879
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发表时间：
2012-12-15
影响因子：
3.2
通讯作者：
Wakaida, I.
中科院分区：
文献类型：
--
作者：
Miyabe, M.;Oba, M.;Wakaida, I.
用吸收光谱研究了Ce烧蚀羽流的时间演化过程。在氦气气氛中，用能量为0.5J/cm(2)的激光二次谐波(532 Nm)烧蚀氧化铈小球。羽流的横向速度(与样品表面水平的膨胀速度)是由样品表面附近测量的吸收光谱的多普勒分裂幅度确定的。通过改变环境气压、烧蚀激光通量、观测时间和观测高度等参数，系统地研究了中性原子和单电离原子的横向速度。此外，通过使探测激光频率与原子共振频率失谐来测量吸收信号的时间分布，以获得速度的时间变化。在阻力模型的基础上，计算了氦气氛中原子和离子物质的减速系数以及真空中的横向速度。这项研究有助于理解羽流动力学对沉积薄膜性能的影响，以及优化基于烧蚀的光谱分析的实验条件。(C)2012年美国物理研究所。[http://dx.doi.org/10.1063/1.4771879]
The temporal evolution of the ablation plume of cerium was investigated by absorption spectroscopy. Cerium oxide pellets were ablated in a helium atmosphere by second-harmonic radiation (532nm) from a Nd:YAG laser at a fluence of 0.5 J/cm(2). The lateral velocity (expansion velocity horizontal to the sample surface) of the plume was determined from the magnitude of the Doppler splitting of the absorption spectra measured close to the sample surface. The lateral velocities of neutral and singly ionized atoms were systematically investigated by varying several parameters, such as ambient gas pressure, ablation laser fluence, observation timing, and observation height. In addition, temporal profiles of the absorption signal were measured by detuning the probe laser frequency from the atomic resonant frequency in order to obtain the temporal variation of the velocity. On the basis of the drag force model, the slowing coefficients for atomic and ionic species in a helium atmosphere were evaluated along with lateral velocity in a vacuum. This study may help in understanding the plume dynamics effect on deposited film properties as well as optimizing experimental conditions for ablation-based spectroscopic analysis. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4771879]