Nitrogen dioxide detection using an optoelectronic sensor

Abstract

Sensitive laser absorption spectroscopy requires a long effective pathlength of the laser beam in the analyzed media. Traditionally, this requirement is satisfied using an optical multipass cell. We present the opportunities of detection of nitrogen dioxide using cavity enhanced spectroscopies. These techniques can be applied for construction of a fully optoelectronic NO 2 sensor with a detection limit better than 1 ppb. The setup usually includes the resonance optical cavity, which is equipped with spherical and high reflectance mirrors, the pulsed or cw laser and a photomultiplier which is connected with the digital oscilloscope or with others digitizers. The optical signal leaving a cavity can be used to determine an absorption coefficient of the intracavity medium.

Cavity Enhanced Absorption Spectroscopy Sensor

“…(8) the detection limit better than 0.5 ppb was obtained for σ = 6 × 10 −19 cm −2 [6][7][8]. It was noticed that, to achieve high value of τ 0 and high precision of the decay time determination, the proper adjustment of the cavity is necessary.…”