Femtosecond third order optical nonlinearity and optical limiting studies of (γ and β)—Barium borate nanostructures

Abstract Single phase (γ and β) barium borate with nanorod structures were prepared by hydrothermal method at reaction conditions of 433 and 1073 K, respectively. FESEM images demonstrated the transformation of nanoclusters into elongated nanorods as the reaction time increased. The third order nonlinear optical (NLO) properties of the samples were investigated by the Z-scan technique (800 nm, 150 fs, 100 MHz). Both phases of barium borate depicted nonlinear absorption and was assigned to the two-photon absorption mechanism. γ–BBO demonstrated negative nonlinear refraction (self-defocusing) while β-BBO showed positive nonlinear refraction (self-focusing). Both the phases exhibited optical limiting behavior and the limiting threshold was found to be in the order of μJ/cm 2 . Nanorods possessed superior third order NLO coefficients compared to nanoclusters of barium borate. Also γ–BBO possessed superior NLO properties compared to β–BBO and it can be strongly emphasized that γ–BBO nanorods can be used as a potential material for photonic applications.