Soft Matter Macro and Micro-Photonics workshop

Ultrafast photonic functions in polymer-structured liquid crystals: From nanocomposite electro-optics to blue-phase ferroelectric nematic

Masanori Ozaki and Kazuma Nakajima

University of Osaka

Polymer-structured liquid crystals enable photonic functionalities that arise from the interplay between liquid-crystal order and polymer morphology. In our earlier studies, we investigated liquid crystal–polymer nanocomposites formed by photopolymerizing mixtures containing reactive mesogenic monomers. Owing to the high miscibility between liquid crystals and mesogenic monomers, the resulting polymer network preserves the macroscopic alignment structure while confining liquid crystal molecules within nanoscale volumes. In such systems, electric-field-induced reorientation occurs without macroscopic structural deformation or light scattering, allowing modulation of the effective refractive index while maintaining the original optical structure. By optimizing the polymerization conditions, particularly the polymerization temperature, electro-optic switching with response times in the microsecond range was achieved.

Building on this concept, we have recently developed a new soft-matter photonic system based on blue-phase polymer templates combined with ferroelectric nematic liquid crystals. The resulting material retains the three-dimensional periodic structure of the blue phase while introducing large spontaneous polarization from the ferroelectric nematic phase. This combination leads to a significant enhancement of the electro-optic response, where voltage polarity reversal induces rapid polarization switching and sub-microsecond birefringence modulation. These results demonstrate that polymer-templated liquid crystal architectures combined with emerging ferroelectric nematic materials provide a promising route toward ultrafast photonic functions in soft-matter systems.