Direct absorption measurement of ambient nitric oxide based on room-temperature pulsed quantum cascade laser

Abstract

The Mid-infrared lasers are very effective for high-sensitive trace gas detection for the fundamental absorption lines of most gases. The quantum cascade (QC) laser, with the advantages of high power, wide tuning range and room-temperature operating conditions, is one of the ideal mid-IR sources developed in these years. The technology combing the room-temperature pulsed quantum cascade laser and the long-path multipass absorption cell can satisfy the need for the sensitivity, selectivity and rapid response. A set of experimental apparatus for the direct absorption measurement of ambient nitric oxide(NO) with the room-temperature pulsed QC laser was presented. With this system a NO concentration of 188ppb was demonstrated, along with an estimated detection limit of 4ppb. The results show that this experimental apparatus can fulfill the detection of NO concentration in ambient air.