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arXiv · 2206.04966

Ferroelectric chiral nematic liquid crystals: New photonic materials with multiple bandgaps controllable by low electric fields

J. Ortega·C. L. Folcia·J. Etxebarria·T. Sierra
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Abstract

We have carried out a spectroscopic study on a prototype ferroelectric nematic material (RM7343) doped with a non-polar chiral compound. The mixture presents two chiral nematic phases, one conventional (N*) and the other polar (NF*), whose behaviours under electric fields E are totally different. On the one hand, the N* phase shows a single reflection band if E is not very high, while fields perpendicular to the helix of a few V/mm are already sufficient to produce multiple bands in the NF* phase. On the other hand, the pitch of the NF* phase grows notably on increasing fields, however remaining practically constant in the N* phase. Both effects have been explained in terms of the different type of interaction with E in each phase (ferroelectric in NF* and dielectric in N*). We argue that the NF* phase behaves as a photonic material with multiple gaps tunable by small fields, which presents important potentialities for applications. A study of the bandgaps has been carried out through the analysis of the dispersion relation of the optical eigenmodes in the NF* phase under field. Finally, an example of the potentialities of the NF* phase within the field of nonlinear optics is briefly presented.

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J. Ortega, C. L. Folcia, J. Etxebarria, T. Sierra. 2022-06-10. Ferroelectric chiral nematic liquid crystals: New photonic materials with multiple bandgaps controllable by low electric fields. https://arxiv.org/abs/2206.04966

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