Xia, Y.Jiang, Y.Fan, R.Dong, Z.Zhao, W.Chen, D.Umesh, G.2026-02-052009Optics and Laser Technology, 2009, 41, 6, pp. 700-704303992https://doi.org/10.1016/j.optlastec.2009.01.011https://idr.nitk.ac.in/handle/123456789/27600The two-photon absorption (TPA) characteristics of PMMA discs doped with three different dyes were studied using an fs-pulsed Ti-Sapphire laser as the pump source, and employing the open-aperture Z-scan technique. TPA cross-sections obtained for PMMA doped with the dyes PM597, DCM and rhodamine 6G-rhodamine B (co-doped) were found to be equal to 24.7, 33.3 and 32.3 GM, respectively (1 GM=10-50 cm4 s phot-1 mol-1). Furthermore, two-photon fluorescence was measured for the samples containing DCM and rhodamine 6G-rhodamine B (co-doped). Compared to the one-photon fluorescence spectrum, the peaks in the two-photon fluorescence spectrum were red shifted and the extent of red shift increased with increasing doping concentration. We have also observed that the red shift in the two-photon fluorescence peak of the samples in the solid form is much larger than that in the solution state. This phenomenon could be explained by a twisted intra-molecular charge transfer model. © 2009 Elsevier Ltd. All rights reserved.Co-dopedDoping concentrationsDye-dopedfs laser pulseOne-photon fluorescencesPump sourcesRed shiftsRed-shiftedRhodamine 6GRhodamine bSolid formsTi sapphiresTwisted intra-molecular charge transfersTwo-photon absorptionTwo-photon fluorescencesUltrafast nonlinearZ-scan techniquesAbsorptionAstrophysicsCharge transferCorundumDoping (additives)Doppler effectFluorescenceGranular materialsIon exchangeLaser pulsesLuminescence of organic solidsMultiphoton processesOptical materialsOptical propertiesPhotolithographyPhotonsPulsed laser applicationsPumping (laser)Light absorption