样品温度对纳秒激光诱导土壤等离子体辐射特性的影响

利用脉宽8 ns，波长为532 nm的Nd:YAG单脉冲纳秒激光器，在一个标准大气压下入射到土壤中(样品土壤来自蚌埠学院校园)，改变样品温度，获得了不同样品温度下激光诱导击穿光谱. 通过分析光谱，得到土壤中不同特征谱线的强度和信噪比. 分别利用Boltzmann斜线法和Stark展宽法计算并分析了等离子体电子温度和电子密度随样品温度的演化规律；同时讨论了提高样品温度和激光诱导土壤等离子体辐射增强的原因. 实验结果表明，随着样品温度的升高，等离子体的谱线强度、信噪比、电子温度和电子密度会逐渐增强，并且在温度为100 °C时达到最大.

Effect of Sample Temperature on Radiation Characteristics of Nanosecond Laser-Induced Soil Plasma

An Nd:YAG single pulse nanosecond laser of 532 nm wavelength with an 8 ns pulse width was projected on the soil samples collected from the campus of Bengbu College under 1 standard atmospheric pressure. Laser-induced breakdown spectroscopy at different sample temperatures was achieved. The intensity and signal-to-noise ratio (SNR) changes of different characteristic spectral lines could be analyzed when the sample temperature changes. The evolution of plasma electron temperature and electron density with the sample temperature was analyzed through Boltzmann oblique line method and Stark broadening method. The cause of the radiation enhancement of laser-induced metal plasma was discussed. Experimental results demonstrated that the spectral intensity, SNR, the electron temperature and electron density of plasma are positively related to the sample temperature, and reach saturation at 100 °C.