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Published on: February 25, 2017
Femtosecond two-photon-excited backward lasing of atomic hydrogen in a flame
Abstract:
We report on an observation of bi-directional 656 nm lasing action of atomic hydrogen in a premixed CH4/air flame induced by resonant femtosecond 205 nm two-photon excitation. In particular, the backward-propagating lasing pulse is characterized in the spatial and temporal domains for the sake of a single-ended diagnostic. Its picosecond-scale duration and smooth temporal profile enable spatially resolved detection of hydrogen atoms in the millimeter range, which is successfully demonstrated using two narrow welding flames.
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