Electrically induced directional self-focusing in electrochromic NiO thin solid films

This report analyzes the asymmetry effects that an electric field can induce on nonlinear optical signals in NiO thin solid films. The samples were prepared in thin film form with approximated thickness of 110 nm by using a spray pyrolysis method. Effects derived from the change in nonlinear refractive index were experimentally evaluated by nanosecond pulses at 532 nm using the z-scan technique. The absence of nonlinear optical absorption was confirmed in this regime before the ablation takes place in the nonlinear media. Numerical simulations were carried out in order to analyze non-reciprocal energy transfer and optical Kerr effect with an influence provided by an applied voltage to the sample studied. Immediate applications for controlling nonlinear waveguiding structures and optical system with multidirectional functions can be envisioned.