The pure P₂(8) line radiation of chemical hydrogen fluoride (HF) laser which can be weakly absorbed by atmosphere was generated using an absorbed module in a line-selected cavity. A numerical model of laser gain was investigated to predict and optimize the laser performance. An experimental verification was carried out in a compact continue wave (cw) tunable chemical HF laser device. It is found that P₁(11) line can be suppressed by fundamental HF particles generated by combustion reaction, meanwhile the proportion of P₂(8) line can be increased close to 100% from original 38%. The absorbance as well as output power of P₂(8) line can also be influenced by concentration of absorbing media.

化学氟化氢（HF）激光的纯P ₂ (8) 线辐射可以被大气弱吸收，它是使用线选择腔中的吸收模块产生的。研究了激光增益的数值模型以预测和优化激光性能。在紧凑型连续波 (cw) 可调谐化学 HF 激光设备中进行了实验验证。发现燃烧反应产生的基本HF粒子可以抑制P ₁ (11)谱线，同时P ₂ (8)谱线的比例可以从原来的38%提高到接近100%。P ₂ (8) 线的吸光度和输出功率也会受到吸收介质浓度的影响。