title: Quantitative gas sensing by backscatter-absorption measurements of a pseudorandom code modulated lambda ~ 8-microm quantum cascade laser.
abstract: We have demonstrated quantitative chemical vapor detection with a multimode quantum cascade (QC) laser. Experiments incorporated pseudorandom code (PRC) modulation of the laser intensity to permit sensitive absorption measurements of isopropanol vapor at 8.0micro . The demonstration shows the practicality of one technical approach for implementing low-peak-power QC lasers in the transmitter portion of a differential absorption lidar (DIAL) system. With a 31-chip, 300-ns/chip PRC sequence, the measured isopropanol detection limit was 12 parts in 10(6) by volume times meters (~3x10(-3) absorption) for a simple backscatter-absorption measurement configuration.
authors: C M
authors: CM
authors: Gittins
authors: E T
authors: ET
authors: Wetjen
authors: C
authors: C
authors: Gmachl
authors: F
authors: F
authors: Capasso
authors: A L
authors: AL
authors: Hutchinson
authors: D L
authors: DL
authors: Sivco
authors: J N
authors: JN
authors: Baillargeon
authors: A Y
authors: AY
authors: Cho