The development of a trace carbon monoxide detector based on mid-infrared quantum cascaded laser

To enhance the detection limitation and sensitivity of carbon monoxide, a trace CO detector is developed. The detector uses a mid-infrared (MIR) quantum cascade laser with centre wavelength at 4.8 m combining MIR multipass herroitt cell with 76 m absorption path length, is capable of improving the detection limitation and sensitivity of carbon monoxide. Meanwhile, an optical structure with dual differential channel paths is integrated to eliminate the instability induced by electrically modulated light source. The experimental results show that the proposed instrument can be applied into in-situ sensitive, rapid and continuous measurements of trace carbon monoxide, with low detection sensitivity down to 40 nmol/mol level in 4 s acquisition time. In addition, operator could substitute a QCL operating at a different wavelength to measure other gases. (authors)