Abstract
An infrared laser heterodyne spectrometer has been developed to measure solar absorption lines of atmospheric minor constituents by using a PbSnTe diode laser and a CO2 laser as local oscillators. The system is capable of operating aboard an airplane in order to detect stratospheric molecules in very low concentrations by observing the sun near sunset or sunrise at the horizontal direction. The test operation on the ground shows that the sensitivity of the photomixer attains the quantum noise limit when a diode laser as well as a CO2 laser is used and the number of absorption lines of stratospheric ozone are successfully measured.
