Femtosecond lidar

Abstract

We sent the slightly, negatively prechirped light of a terawatt femtosecond laser system vertically into the sky and observed the onset of an extended white light channel [1]. The generated plasma channel is highly sensitive to the pulse duration and chirp settings and is most efficient when the group velocity dispersion between laser and focus is fairly well precompensated. Scattered white light from altitudes beyond 12 kilometers was recorded; the spectra exhibit very pronounced features of atmospheric constituents.