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Updated: Jan 25, 2026

An Experimental Protocol for Femtosecond NIR/UV - XUV Pump-Probe Experiments with Free-Electron Lasers
Published on: October 23, 2018
Delay modulation with a glass chopper in pump-probe experiments
S Goharshenasanesfahani1, F Hoveyda1, M Scott-Jones1
1Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky 40292, USA.
Abstract:
A delay modulator, made of glass plates rotating in a pump beam, is applied to measure time-resolved rates of transient processes in a pump-probe experimental setup. Glass plates modulate both delay and beam power. The contribution from the power modulation is subtracted by using a scaled-down measurement made with metal chopper blades. Delay modulation results obtained with this procedure are consistent with the derivative in delay of the usual power modulation and can show a larger signal to noise ratio.
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