Delineating complex ferroelectric domain structures via second harmonic generation spectral imaging

Understanding the mechanisms and spatial correlations of crystallographic symmetry breaking in ferroelectric materials is essential to tuning their functional properties. While optical second harmonic generation (SHG) has long been utilized studies, its capability for probing complex polar yet be fully realized. Here, we develop a SHG spectral imaging method implemented on home-designed laser-scanning microscope, demonstrate application model system (K,Na)NbO 3 single crystals. Supervised fitting analysis produces comprehensive information about polarization vector orientations relative fractions constituent domain variants as well thermal evolution across polymorphic phase transitions. Multiple domains phases are clearly delineated at different temperatures, suggesting competitions . Besides, show that unsupervised matrix decomposition can quickly faithfully reveal configurations without priori knowledge specific material systems. The readily extended other with potentials further enhanced. • Acquisition polarization-dependent image dataset custom-made mode microscope. extract detailed structures. piezoelectric (K, Na)NbO crystal system.