激光诱导击穿光谱(laser-induced breakdown spectroscopy, LIBS)在煤质在线监测方面展现了突出的应用前景和研究价值。 针对该技术在实际应用中会由于脉冲激光功率起伏导致的长期测量稳定性差的问题, 建立了闭环负反馈式脉冲激光功率锁定装置, 采用激光功率负反馈信号控制和锁定Nd∶YAG激光器输出功率。 实验研究了不同分光比例脉冲激光器锁定在设定输出功率, 同一分光比例激光器锁定在不同输出功率以及长时间运行时的功率锁定。 结果表明, 不同的分光比例对激光输出功率的锁定效果影响不大, 分光比例越小, 稳定速度越快; 同一分光比例实现激光脉冲功率不同预设值的锁定以及在长时间运行时, 采用此装置进行功率锁定后, 激光输出功率处于预设区间内, RSD值由自由运行时的2.4%降低至1.1%。

Laser-induced breakdown spectroscopy (LIBS) as a rapid spectral analysis technology shows the outstanding application foreground and research value in coal quality on-line monitoring. In the practical application of this technology, the pulsed laser power fluctuation leads to the worse performance of long term stability, so a closed-loop feedback pulsed laser power locking device is set up, using laser power feedback signal to control and lock Nd∶YAG laser output power. The laser power locking experiments are investigated in the same pre-set value with different splitting ratios, the different laser output power with the same proportion and the long time running modes. The results show that the beam split ration has little impact to the stability of the laser power, and the smaller split ration leads to the faster stabilization. This device can keep the output power of the pulsed laser being locked in the pre-set range for a long-term running, RSD values decrease from 2.4% of free-running to 1.1%.