Femtosecond optical Kerr-gate measurement of fluorescence spectra of dye solutions

Utilizing the ultrafast electronic response of Kerr effect of glass material as an optical gate, we have constructed a system for the time-resolved fluorescence measurement in the 100-fs time region. We have demonstrated that the ultrafast Kerr-gate technique combined with multi-channel spectral detection enables us to the direct measurement of the spectral shape. Because of highly efficient gating and simultaneous acquisition of all the spectral components, the time-resolved fluorescence spectra of high S/N ratio have been obtained for several dye solutions. Although wavelength-dependent time delay of the system is found to remain, direct recognition of the dynamic Stokes shift in the S-2 --> S-0 fluorescence of malachite green in ethanol has been made by comparing the obtained time-resolved spectra with those of the ultrafast fluorescence of beta-carotene in hexane. (C) 2000 Published by Elsevier Science B.V. All rights reserved.