基于TDLAS-WMS的高灵敏度电子鼻传感器设计

为了对痕量有害气体(甲烷为例)进行非接触式检测,本文基于可调谐二极管激光吸收光谱(TDLAS)与波长调制光谱(WMS)相结合的检测技术,采用中心波长为7.5μm的量子级联激光器(QCL),设计并研制出高灵敏度电子鼻传感器系统.在室温条件下,通过调节QCL注入电流,使其发光光谱扫过甲烷(CH4)气体吸收谱线.同时采用紧凑型herriott气室(长度为40 cm,容积为800 m L),使得系统总光程达到16 m.利用该传感器系统,对不同浓度的CH4进行测量,结果显示,测量相对误差小于7%,检测下限为1×10~(-9).同时,研究人员可以通过更换其他激射波长的QCL,实现对其它有害气体的检测.

Design of electronic nose sensor with high sensitivity based on TDLAS-WMS

In order to carry out the non-contact type detection of trace noxious gas(methane), based on the detection technology in combination with both tunable diode laser absorption spectroscopy(TDLAS)and wavelength modulation spectroscopy(WMS), the quantum cascaded laser(QCL)with the centre wavelength of 7.5 μm was adopted, and an electronic nose system with high sensitivity was designed and developed. At room temperature, the luminescent spectrum of QCL could scan the methane(CH₄)absorption line through adjusting the injection current of QCL. In addition, a compact herriott gas cell with a length of 40 cm and a volume of 800 mL was adopted to achieve the total optical path of 16 m. The methane with different concentrations was detected with the developed sensor system. The results show that the relative detection error is less than 7%, and the minimum detection limit is 1×10^-9. Moreover, the detection of other harmful gases can be realized through replacing QCL with other emitting wavelength.