Shettigar, S.Umesh, G.Poornesh, P.Manjunatha, K.B.Asiri, A.M.2026-02-052009Dyes and Pigments, 2009, 83, 2, pp. 207-2101437208https://doi.org/10.1016/j.dyepig.2009.04.009https://idr.nitk.ac.in/handle/123456789/27579The third-order nonlinear optical properties of two novel styryl dyes, namely, 1,3-diethyl-5-(4-methoxybenzylidene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione and 5-(3,4-dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione were studied using the Z-scan technique employing 7 ns laser pulses at 532 nm. The nonlinear refractive index, nonlinear absorption coefficient, magnitude of effective third-order susceptibility and coupling factor were determined. The optical power limiting behavior of the colorants was ascribed to two-photon absorption phenomenon. Nonlinear absorption cross-section increased with increase in ? electron density and the effective two-photon absorption cross-section was two orders of magnitude larger than those of commercially available azo compounds. The results suggest that these colorants offer promise as nonlinear optical materials for device applications. © 2009 Elsevier Ltd. All rights reserved.Coupling factorNonlinear absorptionNonlinear refractionOptical power limitingStyryl dyesZ-scanAbsorptionData processingLaser pulsesLight absorptionLuminescence of organic solidsNonlinear opticsOptical materialsPhotonsPulsed laser applicationsRefractionRefractive indexSingle crystalsSulfur compoundsMultiphoton processesabsorptioncolorcouplingdyeinorganic compound