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Updated: Aug 20, 2026

A Novel Technique for Raman Analysis of Highly Radioactive Samples Using Any Standard Micro-Raman Spectrometer
Published on: April 12, 2017
Coherent two-photon absorption spectroscopy of the Raman-active KGd(WO4)2 crystal
Arkady Major1, J Stewart Aitchison, Peter W E Smith
1Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada. a.major@utoronto.ca
Abstract:
We report on the systematic open-aperture Z-scan characterization of the two-photon absorption properties in one of the most efficient solid-state Raman frequency shifters, the crystal potassium gadolinium tungstate [KGd(WO4)2]. The two-photon absorption coefficient was determined in the 370-600-nm wavelength range, with the highest value found to be approximately 1.9 cm/GW at 370 nm. Nonlinear losses are crucial in determining the conversion efficiency of the stimulated Raman scattering process when it is excited with ultrashort laser pulses with photon energy exceeding half of the bandgap. In addition, the results were analyzed within the context of a simple two-parabolic-band theoretical model to yield an effective bandgap energy value for the crystal.
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