Modeling nonlinear optical polarization microscopy for visualizing magnetic domain walls

Abstract

In this work, we present numerical modeling of nonlinear second harmonic generation polarization microscopy for visualization and differentiation of Bloch- and Néel-type magnetic domain walls. The developed model accounts for the spatial distribution of pump and second harmonic fields in various polarization configurations. Our results demonstrate the capability not only to detect the presence of domain boundaries but also to distinguish their types based on characteristic features in the SHG intensity distribution. It was observed that at certain pump polarization angles, the contrast between magnetic domains vanishes, enabling selective visualization of domain walls exclusively. A qualitative difference in SHG response between Bloch- and Néel-type domain walls was identified. The presented approach offers promising prospects for the investigation of more complex magnetic structures using nonlinear optical microscopy methods.