Abstract

Useful application of the differential absorption lidar (DIAL) technique requires a transmitter that conforms to stringent spectral specifications. For example, wavelength-dependent absorption of the laser transmission leads to a systematic underestimation of the optical depth; to limit the error to 1% requires a laser linewidth on the order of 10% of the absorption linewidth. Additional underestimation due to ASE presents a requirement for laser spectral purity of better than 99.5% for errors of no more than 3% over a typical measurement range; errors of <1% require 99.9% spectral purity.

© 1996 Optical Society of America