RESUMO
In this work, we report on the fabrication, characterization and the third-order nonlinear optical (NLO) properties of basic blue 7 (BB 7) dyeâdoped polyvinyl alcohol (PVA) polymer thin films. The absorption spectra of BB 7 dyeâPVA films were measured by UVâvisible absorption studies. The functional groups of BB 7âPVA films have been identified by FTâIR spectroscopic analysis. The surface morphology was examined by AFM and SEM analysis which shows that the BB 7 dyeâdoped PVA films have a homogenous and smooth surface. The nonlinear absorption and refraction of BB 7âPVA films were respectively explored by open aperture and closed aperture Zâscan technique using a 5 mW semiconductor diode laser of 635 nm wavelengths. The BB 7âPVA films exhibit the reverse saturable absorption (RSA) and self-defocusing effect and the measured thirdâorder nonlinear susceptibility χ(3) values of these films were found to be of the order of 10- 5 esu. The present experimental results show that BB 7âPVA films may have potential applications in future photonic and NLO devices.