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Updated: May 26, 2026
Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Rapid passage signals from a vibrationally excited target molecule: a pump and probe experiment with continuous wave
R J Walker1, J H van Helden, J Kirkbride
1Department of Chemistry, The Physical and Theoretical Chemistry Laboratory, The University of Oxford, Oxford, UK.
Abstract:
Two 5 µm continuous wave quantum cascade lasers are used to perform a counterpropagating pump and probe experiment on a low pressure sample of nitric oxide. The strong pump field excites a fundamental rovibrational transition and the weaker probe field is tuned to the corresponding rotationally resolved hot band transition. When both light fields are in resonance, rapid passage is observed in the hot band absorption lineshape arising from a minimally damped and velocity-selected sample of molecules in the v=1 state. The measured rapid passage signals are well described by a two-level model based on the optical Bloch equations.
