宽带腔增强吸收光谱技术应用于痕量气体探测及气溶胶消光系数测量

基于氙灯的非相干宽带腔增强吸收光谱系统, 并将其应用于痕量气体及气溶胶消光系数的测量. 该系统的探测灵敏度通过测量NO₂在520—560 nm波长范围内的吸收得到验证, 最小可探测灵敏度为1.8× 10^-7cm^-1 (1σ, 0.12 s积分时间, 50次平均), 对应的NO₂探测极限～33 nmol/mol. 结合标准气溶胶粒子发生系统, 测量了不同浓度的单分散硫酸铵气溶胶粒子在532 nm波长处的消光系数, 得到粒径为600 nm的硫酸铵气溶胶的消光截面为1.12× 10^-8cm², 与文献报道值1.167× 10^-8cm²相一致, 验证了气溶胶测量的可行性和准确性.

Incoherent broadband cavity enhanced absorption spectroscopy for trace gases detection and aerosol extinction measurement

We report on the development of incoherent broadband cavity enhanced absorption spectroscopy system based on a short arc Xenon lamp for trace gas detection and aerosol optical properties measurements.A minimum detection sensitivity of 1.8×10^-7 cm^-1（1σ,0.12 s integrating time,and 50 times average） is obtained on the basis of absorption spectroscopy of NO₂ in a spectral range of 520-560 nm,which corresponds to a minimum detection concentration of～33 nmol/mol for NO₂.Combining a laboratory aerosol generation system,the extinction coefficients of 600 nm diameter monodispersed ammonium sulfate aerosol are measured under different particle concentrations.A cross-section of 1.12×10^-8cm² for ammonium sulfate at 532 nm wavelength is obtained, which agree well with the literature result of 1.167×10^-8cm².The results demonstrate the ability of our system to quantitativly measure aerosol optical properties.