Nonlinear Optical Imaging of Polar Topological Textures in Ferroelectric Materials

Session Information

Location: amf. P7 | "Gheorghe Asachi" Technical University of Iași (TUIAȘI)
Day: 3. Wednesday 17
Time: 09:00-10:00
Chairperson: Paul Gavriloaea

Presentation Details

Presentation Type: Oral presentation
Title: Nonlinear Optical Imaging of Polar Topological Textures in Ferroelectric Materials
Abstract: The emergence of topological polarization textures in ferroelectric materials is reshaping our understanding of ferroic order, extending it beyond uniform states toward complex, spatially structured configurations. Non-Ising and chiral domain walls, bubble domains, (anti)vortices, and polar (anti)skyrmions illustrate how symmetry breaking, electrostatic boundary conditions, and reduced dimensionality give rise to rich polarization landscapes with functional potential.
A central challenge in this context is the development of imaging approaches capable of resolving such polarization textures in three dimensions, while preserving sensitivity to symmetry and chirality. Second-harmonic generation (SHG) microscopy provides a powerful platform in this regard, owing to its intrinsic sensitivity to broken inversion symmetry and polarization orientation [1]. In particular, SHG polarimetry enables the reconstruction of complex polar states [2,3] and the discrimination between different polar topological structures such as chiral Bloch walls, non-Ising Néel walls, and Bloch lines [4].
In this talk, I will present recent advances in SHG-based imaging of polar topological textures, combining polarimetric measurements with machine-learning-assisted analysis [5,6] to achieve rapid and quantitative 3D mapping of polarization fields. I will further show how circular dichroism in SHG (CD-SHG) can be harnessed to probe chiral ferroic states. The developed polarimetry and symmetry analysis framework establish SHG microscopy and CD-SHG, as reliable approaches for imaging and characterization of polar topological textures. It contributes to the broader effort of defining and probing complex ferroic states, and provides a general framework for nonlinear optical studies of ferroic order in anisotropic materials.

References
[1] Cherifi-Hertel et al., J. Appl. Phys. 129(8), 081101 (2021) https://doi.org/10.1063/5.0037286
[2] Acevedo-Salas et al., Nano Letters 23, 3, 795–803 (2023) https://doi.org/10.1021/acs.nanolett.2c03579
[3] Croes et al., Phys. Phys. Rev. Materials 5, 124415 (2021) https://link.aps.org/doi/10.1103/PhysRevMaterials.5.124415
[4] Cherifi-Hertel et al., Nature Communications 8, 15768 (2017). https://doi.org/10.1038/ncomms15768
[5] Croes et al. Advanced Physics Research 2: 2200037 (2022). https://doi.org/10.1002/apxr.202200037
[6] Croes and Cherifi-Hertel, Vision2P https://hal.science/hal-05056312, https://github.com/Electromag-IPCMS/Vision2P

Presenter

Dr Salia Cherifi-Hertel
CNRS and University of Strasbourg, IPCMS | France

Authors

1. Cherifi-Hertel, Salia | Université de Strasbourg, CNRS, IPCMS