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Updated: Aug 22, 2026

Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Flow imaging by use of femtosecond-laser-induced two-photon fluorescence
James B Kelman1, Douglas A Greenhalgh, Euan Ramsay
1Cranfield University, Cranfield MK43 0AL, United Kingdom. j.kelman@cranfield.ac.uk
Abstract:
A novel technique is demonstrated for the imaging of turbulent flows in which a single window to the flow is the only optical access required. A femtosecond laser is used to excite two-photon fluorescence in a disodium-fluorescein-seeded water jet. The fluorescence signal is generated at only the focal point of the laser because of the highly nonlinear nature of the two-photon absorption, and it is collected in a direction counterpropagating to the excitation beam. Tight focusing of the laser is used to limit the probe volume, and the two-dimensional mean and rms concentration images are collected by raster scanning the laser.
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