Abstract

Coherent differential absorption lidar (DIAL) systems employing infrared lasers (such as CO₂ or Ni:MgF₂) promise to be extremely useful tools for remote sensing of atmospheric pollutants. Most research to date has concentrated on systems employing transverse electric discharge, atmospheric pressure (TEA) CO₂ lasers. These are low pulse repetition frequency (PRF), high pulse energy devices and can be used to make DIAL measurements at very long ranges. However, it will be shown that in many applications TEA laser DIAL systems have greatly inferior performance to high-PRF repetitively Q-switched, cw discharge CO₂ laser DIAL systems. Laser PRF is a major factor in determining coherent DIAL performance. In this paper we will quantify the effects of laser PRF on concentration measurement accuracy, maximum usable range, and ambiguous range.

© 1983 Optical Society of America