DAYTIME MESOPAUSE TEMPERATURE-MEASUREMENTS WITH A SODIUM-VAPOR DISPERSIVE FARADAY FILTER IN A LIDAR RECEIVER

Using a dispersive Faraday bandpass filter, we have upgraded our Na te mperature lidar to be capable of 24-h operation. Along with a transmit ting telescope to reduce the laser beam divergence to 0.2 mrad, the in itial use of this unique narrow-band filter in a lidar receiver allowe d us to reduce the detected daytime sky background to a level previous ly encountered at night, making routine daytime temperature measuremen ts in the mesopause region a reality. The implementation, characteriza tion, and results of what we believe are the first daytime mesopause t emperature measurements are reported. (C) 1996 Optical Society of Amer ica