掺Er^(3+)光学玻璃激光诱导击穿光谱特性研究

Properties of Er^(3+) Doped Optical Glasses by Laser-Induced Breakdown Spectroscopy

利用激光诱导击穿光谱(LIBS)技术,研究了延迟时间、激光能量和激光脉冲重复频率对掺Er3+光学玻璃等离子体发射光谱的影响。给出了获得谱线品质优良的实验条件,并标定Er II 337.27nm,Er II 349.91nm为分析谱线。实验结果表明:样品在ICCD采集延时为175ns时可以避免等离子体产生初期背景噪声对谱线的影响;谱线强度和信背比随激光能量增加而变化,在75~100mJ间呈线性变化,随后呈缓变增加,激光能量大于120mJ后呈下降趋势,但谱线强度最大值出现时间随激光能量增加而变短;在激光能量120mJ,延迟时间为175ns时,谱线强度随激光脉冲重复频率(1~10Hz)增加而增加,但重复频率为3.3Hz时谱线强度测量相对标准误差最小,其RSD为3.8%。由此可见通过实验合理确定延迟时间、激光能量和激光脉冲重复频率,有利于提高激光诱导击穿光谱分析的精确度。

With the laser induced breakdown spectroscopy （LIBS） technology, the effect of delay time, laser energy and the la ser pulse repetition frequency on the plasma emission spectroscopy of Era＋ doped optical glass is studied. The condition to get the spectral lines of the best quality is achieved, and the lines of the Er II 337.27 nm and Er II 349.91 nm are calibrated for a- nalysis. Experimental results show., firstly, the influence of the background noise on the initial plasma spectral lines can be a voided when the delay time is the 175 ns. Secondly, the spectrum intensity and the signal to background ratio change with the increase of the laser energy. They change linearly between 75 mJ and 100 mJ then increase slowly and decrease with the laser energy above 120 mJ. However, the presentation time of the spectrum peaks shortens with the increase of the laser energy. Lastly, when the laser energy is 120 mJ and delay time 175 ns, the spectrum intensity increases with the increase of the laser pulse repetition frequency （1-10Hz） but when the repetition frequency is 3.3Hz, the relative standard error of spectrum inten sity measurement is minimum, and the RSD is 3.8%. Consequently, the analysis accuracy of LIBS can be improved through experiments to determine a reasonable delay time, laser power and laser pulse repetition frequency.