激光修锐青铜金刚石砂轮的等离子体光谱

Plasma Emission Spectra During Laser Dressing of Bronze-Bonded Diamond Wheel

对不同激光参数条件下脉冲光纤激光修锐青铜金刚石砂轮过程中产生的490-600 nm波段范围内的等离子体空间分辨发射光谱进行了研究。在局部热力学平衡条件下，根据测得的等离子体谱线信号的相对强度，利用Boltzmann图法和Stark展宽法分别计算得到等离子体电子温度和电子数密度值，并对激光单脉冲能量、距砂轮表面的探测距离等因素对等离子体电子温度和电子数密度的影响进行了研究。实验结果表明，激光修锐产生的等离子体电子温度和电子数密度随探测距离的增加近似呈Lorentz分布，随激光单脉冲能量的变化近似呈指数规律增长。在此基础之上，进一步计算了等离子体逆韧致吸收系数，并总结其随探测距离和激光单脉冲能量的变化规律。

The spatial evolution of the plasma emission spectra in the wavelength range of 490-600 nm during pulsed fiber laser dressing of bronze-bonded diamond grinding wheel under different laser conditions are studied. Under the assumption of local thermodynamic equilibrium, the electron temperature is determined from the Boltzmann plot method whereas the electron number density is calculated from the Stark broadened profiles according to the experimentally observed line profiles of neutral copper. Besides, the variations of the electron temperature and the electron number density as a function of the single-pulse laser energy at different distances along the direction of propagation of the plasma are studied. The results show that the electron temperature and density take on the Lorentz distribution as the distances increases, and they increase exponentially as the single-pulse laser energy increases. In addition, the behavior of the inverse bremsstrahlung absorption coefficient with the detecting distance and the single-pulse laser energy is also discussed.