Novel pulsed and cw quantum cascade distributed feedback (QC-DFB) lasers operating near lambda=8 micrometers were used for detection and quantification of trace gases in ambient air by means of sensitive absorption spectroscopy. N2O, 12CH4, 13CH4, and different isotopic species of H2O were detected. Also, a highly selective detection of ethanol vapor in air with a sensitivity of 125 parts per billion by volume (ppb) was demonstrated.

中文翻译：

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量子级联激光器的吸收光谱。

新型脉冲和连续量子级联分布反馈（QC-DFB）激光器在λ= 8微米附近工作，用于通过灵敏吸收光谱法检测和定量环境空气中的痕量气体。检测到N2O，12CH4、13CH4和不同的H2O同位素。另外，还证明了对空气中乙醇蒸气的高选择性检测，灵敏度为每十亿分之125（ppb）。