Absolute density measurement of nitrogen dioxide with cavity-enhanced laser-induced fluorescence

Abstract

The absolute number density of nitrogen dioxide (NO 2 ) seeded in argon is measured with cavity-enhanced laserinduced fluorescence (CELIF) through using a pulsed laser beam for the first time. The cavity ring down (CRD) signal is acquired simultaneously and used for normalizing the LIF signal and determining the relationship between the measured CELIF signal and the NO 2 number density. The minimum detectable NO 2 density down to (3.6±0.1)×10 8 cm −3 is measured in 60 s of acquisition time by the CELIF method. The minimum absorption coefficient is measured to be (2.0±0.1)×10 −10 cm −1 , corresponding to a noise equivalent absorption sensitivity of (2.2±0.1)×10 −9 cm −1 •Hz −1/2 . The experimental system demonstrated here can be further improved in its sensitivity and used for environmental monitoring of outdoor NO 2 pollution.

Synchronous detection of multiple optical characteristics of atmospheric aerosol by coupled photoacoustic cavity

“…In order to accurately detect the optical characteristic parameters of aerosols, the filter technology, [6] cavity ring-down spectrometer (CRDS), [7,8] photoacoustic spectroscopy (PAS), [9,10] cavity enhanced absorption spectroscopy (CEAS), [11,12] and laser induced fluorescence technology (LIF) [13,14] have emerged successively, and the extinction coefficient and absorption coefficient of aerosols have been measured by the above technologies. Among them, Chen et al [15] developed a set of aerosol absorption coefficient measurement system by using photoacoustic spectroscopy technology, and successfully measured the aerosol absorption coefficient of the ambient atmosphere.…”

High-sensitivity methane monitoring based on quasi-fundamental mode matched continuous-wave cavity ring-down spectroscopy

“…Accurate access to atmospheric greenhouse gases data will be the primary problem to help the world solve the climate crisis. However, the concentrations of many greenhouse gases [2][3][4][5] in the atmosphere are only ppm or even ppb, such as methane (∼ 2 ppm), nitrous oxide (∼ 330 ppb), and carbon monoxide (∼ 30 ppb). When measuring these ultra-trace gases, more sensitive monitoring techniques are required, [6][7][8][9] such as cavity-enhanced absorption spectroscopy (CEAS), [10] and quartz-enhanced photoacoustic spectroscopy (QEPAS) [11] technology.…”