Femtosecond Z-scan measurement of third-order nonlinear optical response of fluorine-doped tin oxide

The excitation wavelength dependent nonlinear optical response of fluorine-doped tin oxide (FTO) is systematically studied by the Z-scan technique. The broadband third-order nonlinear optical properties of FTO are verified and a value of nonlinear refractive index coefficient n (2) to be 2.52 x 10(-16) m(2) W-1 is obtained at epsilon-near-zero region. Meanwhile, a large modulation depth and nonlinear absorption coefficient beta are estimated about 9.61% and -1.96 x 10(-9) m W-1, respectively. The experimental results indicate that FTO is a promising nonlinear optical material and has great application potential in the field of nonlinear optical devices.