Liquid-crystal-based topological photonics

Proceedings of the National Academy of Sciences, vol. 118

Abstract

Liquid crystals are complex fluids that allow exquisite control of light propagation thanks to their orientational order and optical anisotropy. Inspired by recent advances in liquid-crystal photo-patterning technology, we propose a soft-matter platform for assembling topological photonic materials that holds promise for protected unidirectional waveguides, sensors, and lasers. Crucial to our approach is to use spatial variations in the orientation of the nematic liquid-crystal molecules to emulate the time modulations needed in a so-called Floquet topological insulator. The varying orientation of the nematic director introduces a geometric phase that rotates the local optical axes. In conjunction with suitably designed structural properties, this geometric phase leads to the creation of topologically protected states of light. We propose and analyze in detail soft photonic realizations of two iconic topological systems: a Su-Schrieffer-Heeger chain and a Chern insulator. The use of soft building blocks potentially allows for reconfigurable systems that exploit the interplay between topological states of light and the underlying responsive medium.

Authors 4

1. Hamed Abbaszadeh Aachen Instituut-Lorentz

   Leiden University

   Affiliation as printed

   Instituut-Lorentz, Universiteit Leiden, Leiden 2300 RA, The Netherlands;

2. Michel Fruchart

   University of Chicago

   Affiliation as printed

   Department of Physics, University of Chicago, Chicago, IL 60637;

   James Franck Institute, University of Chicago, Chicago, IL 60637;

3. Wim van Saarloos Aachen Instituut-Lorentz

   Leiden University

   Affiliation as printed

   Instituut-Lorentz, Universiteit Leiden, Leiden 2300 RA, The Netherlands;

4. Vincenzo Vitelli corresponding

   University of Chicago

   Affiliation as printed

   Department of Physics, University of Chicago, Chicago, IL 60637;

   James Franck Institute, University of Chicago, Chicago, IL 60637;

   Kadanoff Center for Theoretical Physics, University of Chicago, Chicago, IL 60637