Study of nonlinear optical properties of pure and Mg-doped ZnO films

Abstract

We report the nonlinear optical properties in pulsed laser deposited pure and Mg-doped ZnO films at an excitation energy (1.95 eV) much smaller than the band gap energies (3.24 eV) of the films. The nonlinear absorption is attributed to the presence of defect states whereas the nonlinear refraction arises due to thermal lensing effect. Larger contribution of nonlinear absorption compared to nonlinear refraction suggests the utility of Mg-doped ZnO films in optical limiting device applications.