Femtosecond nonlinear refraction of 2D semi-metallic redox exfoliated ZrTe2 at 800 nm

Abstract

Zirconium telluride, a transition metal dichalcogenide, was synthesized by a redox exfoliated method to obtain a 2D monolayer semi-metal. After being characterized for compositional and optical analysis, its third-order nonlinear optical (NLO) properties were studied by the Z-scan technique in the femtosecond (100 fs) regime at 800 nm. Interestingly, in this spectro-temporal regime and in the intensity range exploited, the only third-order NLO effect observed was nonlinear refraction, giving rise to a positive value of the nonlinear refractive index coefficient, n2 = +(4.2 ± 0.3) × 10−16 cm2/W. Based on the calculated band structure and the excitation photon energies employed, the physical origin of the refractive nonlinearity is discussed.