Abstract

We have transmitted 0.5890-nm laser produced sodium resonance radiation vertically into the earth’s atmosphere and have observed that the amount of radiation backscattered from the 90-km altitude sodium layer depends on the polarization of the transmitted laser radiation. As the polarization of the laser radiation was changed from linear to circular polarization, the backscattered signal from the sodium layer increased by 30% when averaged over the entire fluorescent spot in the mesosphere with an 80% increase at the center of the fluorescent spot. In addition, the backscattered signal as a function of the frequency tuning of the laser radiation was symmetric for linear polarization and asymmetric for circular polarization. These data are consistent with optical pumping of the sodium atoms.

© 1991 Optical Society of America