抄録
We have developed single-mode quantum cascade lasers (QCLs) emitting at 5.2μm and 7.7 Em. Single-mode emission with narrow line width is achieved using a distributed feedback (DFB) technology. A narrow line width is interpreted in terms of an extremely small effective coupling efficiency of spontaneous emission, caused by ultrafast nonradiative scatterings. We have demonstrated absorption signal detection of NO, N2O, and CH4. The highest spectral resolution can be achieved with a CW mode DFB-QCL. We have observed lines of isotopomer of nitrous oxide, and signal detection limit is about 50 ppb.
