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 8.0 μm. 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 106 by volume times meters (∼3 × 10-3 absorption) for a simple backscatter-absorption measurement configuration.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics