Ferroelectric nematic liquid crystal phase.
Nematic liquid crystals (NLCs) have been known for years and are broadly exploited in modern display technologies, constituting a multibillion business. The key aspect of their applicability is the unique combination of fluidity, anisotropic physical properties and processability. The “standard” NLC state is uniaxial and non-polar. A polar counterpart was already envisioned more than a hundred years ago by M. Born, but it was not until 2017 that they were experimentally realized.
We participated in the seminal investigations of this new set of materials. The field of ferroelectric nematics has been recognized as an emerging field by the American Physical Society by the invitation to contribute the first Perspectives Phys. Rev. E manuscript:
- N. Sebastian, M. Čopič and A. Mertelj, “Ferroelectric nematic liquid-crystalline phases”, (Perspectives series), Phys. Rev. E., 2022, 106, 021001-1-021001-27 doi: 10.1103/PhysRevE.106.021001. PDF: PhysRevE.106.021001
Among various things, our research is focused on:
Effective patterning of electric polarization structures in ferroelectric nematic liquid crystals via exploitation of flexoelectric coupling effects.
- N. Sebastian, M. Lovšin, B. Berteloot, N. Osterman, A. Petelin, R.J. Mandle, S. Aya, M. Huang, I. Drevenšek-Olenik, K. Neyts, A. Mertelj, “Polarization patterning in ferroelectric nematic liquids”, preprint available in https://arxiv.org/abs/2301.07933
Investigations of the mechanisms leading to the occurrence of nematic polar order in these materials:
- R.J. Mande, N. Sebastian, J. Martinez-Perdiguero and A. Mertelj, “On the molecular origins of the ferroelectric splay nematic phase”. Nature Communications. 2021, 12, 4962-1-4962-12, doi: 10.1038/s41467-021-25231-0.
- N. Sebastian, L. Cmok, R.J. Mandle, M.R. de la Fuente, I. Drevenšek-Olenik, M. Čopič and A. Mertelj, “Ferroelectric-ferroelastic phase transition in a nematic liquid crystal”. Phys. Rev. Lett., 2020, 124, 037801-1-037801-6. doi: 10.1103/PhysRevLett.124.037801, PDF: PhysRevLett.124.037801 Featured as Editor’s suggestion and Featured in Physics Today: https://doi.org/10.1063/PT.3.4448
- A. Mertelj, L. Cmok, N. Sebastián, R. J. Mandle, R. R. Parker, A. C. Whitwood, J. W. Goodby and M. Čopič. Splay nematic phase. Phys. Rev. X, 2018, 8(4), 041025-1-041025-12, doi: 10.1103/PhysRevX.8.041025. Featured in Physics Today: https://doi.org/10.1063/PT.3.4448
Complex electro-optic behavior and modelling.
- N. Sebastian, R.J. Mande, A. Petelin, A. Eremin and A. Mertelj, “Electrooptics of mm-scale polar domains in the ferroelectric nematic phase”. Liquid Crystals. 2021, 48, 14, 2055-2071. Doi: 10.1080/02678292.2021.1955417. Finalist of the 2021 Luckhurst-Samulski Prize https://doi.org/10.1080/02678292.2022.2145695
Microstructuring liquid crystals.
Different LC phases are also studied and their possible use for applications. Within the International Sino-Slovenian joint research Center on Liquid Crystal Photonics at Nankai University in China we investigate optical properties of microstructured polymer-liquid crystal supperlatices. We explore their tunable optical diffractive characteristics and their possible use as active media for optical amplification and lasing.
- Y. Wang et al., Tunable Topological Lasing of Circularly Polarized Light in a Soft-matter-based Superlattice, to appear in Laser &Photonic Reviews 2023, DOI: 10.1002/lpor.202200643 (https://arxiv.org/pdf/2205.06536)
- D. Bošnjaković, X.Zhang, I. Drevenšek Olenik,”Tuneable optical diffractive structures from liquid crystalline materials incorporated into periodic polymeric scaffolds.”Liquid crystals. 2023, 14. DOI: 10.1080/02678292.2022.2161020.
- D. Yang, M. Chemingui, Y. Wang, X. Zhang, I. Drevenšek-Olenik, F. Hassan, Q. Wu, Y. Li, L. Saadaoui, J. Xu. “Dual-wavelength lasing with orthogonal circular polarizations generated in a single layer of a polymer–cholesteric liquid crystal superstructure”. Polymers. 2023, 15, 1226, 12,DOI: 10.3390/polym15051226.
- D. Bošnjaković, M. Fleisch, X. Zhang, I. Drevenšek-Olenik, “Electrically tuneable optical diffraction gratings based on a polymer scaffold filled with a nematic liquid crystal.”Polymers. 2021, 13, 2292, 17. DOI: 10.3390/polym13142292.
- S. Gao, J. Wang, W. Li, X. Yu, X. Zhang, X. Song, A. Iljin, I. Drevenšek-Olenik, R.A. Rupp, J. Xu. “Low threshold random lasing in dye-doped and strongly disordered chiral liquid crystals.”Photonics research. 2020, 8, 5, 642-647, DOI: 10.1364/PRJ.388706.
- D. Bošnjaković, N. Sebastián, I. Drevenšek Olenik, “Magnetically tunable liquid crystal-based optical diffraction gratings.”Polymers. 2020, 12, 2355, 15. DOI: 10.3390/polym12102355.