Absorption measurements in continuous high-power CO2 laser processing of materials
Absorption measurements in continuous high-power CO2 laser processing of materials
复制标题
连续高功率 CO2 激光材料加工中的吸收测量
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
V. Granier
中科院分区：
文献类型：
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作者：
R. Fabbro;D. Bermejo;J. Orza;L. Sabatier;L. Leprince;V. Granier
当用从10 3 到10 7 瓦/cm 2 变化的激光强度在氦气屏蔽下照射钢(35 NCD 16)和纯铁的金属靶时，测量了CO 2 激光的吸收系数。所使用的诊断装置由一个积分球组成，该积分球收集目标反射的所有激光。该设置允许该测量的时间分辨率约为 0. 1 ms。随着激光强度的增加，吸收增加的时间依赖性与等离子体光度的出现之间存在明显的相关性。对于更高的强度，当达到锁孔状态时，这种相关性消失并且吸收达到 95%。这种非常高的吸收水平被解释为激光在锁孔内的几何捕获以及等离子体羽流吸收对此过程的贡献较低的结果。
The absorption coefficient of the C02 laser light has been measured when metallic target of steel (35 NCD 16) and pure iron are irradiated with laser intensities varying from i03 to lO7Watt/cm 2 with helium gas shielding. The diagnostic used consists of an integrating sphere which collects all the laser light reflected by the target. This set-up allows a temporal resolution of this measurement of about 0. 1 ms. As the laser intensity increases, a clear correlation between the time-dependance of the increase of absorption and of the appearance of the plasma luminosity is evidenced. For higher intensities, when a keyhole regime is reached, this correlation disappears and the absorption reaches 95 %. This very high level of absorption is interpreted as a result of the geometrical trapping of the laser light inside the keyhole and a low contribution of plasma plume absorption to this process.