Topological Interface-State Lasing in a Polymer-Cholesteric Liquid Crystal Superlattice

TL;DR

This paper demonstrates tunable topological lasing with circular polarization in a polymer-cholesteric liquid crystal superlattice, enabling robust, low-threshold, visible-wavelength laser devices with potential for integrated photonics.

Contribution

It introduces a novel polymer-cholesteric liquid crystal superlattice with engineered topological interface states for lasing, combining topological physics with soft-matter photonics.

Findings

Achieved low-threshold topological lasing at 0.4 μJ

Demonstrated thermal tuning of emission wavelength

Realized circularly polarized lasing in a soft-matter platform

Abstract

The advance of topological photonics has heralded a revolution for manipulating light as well as for the development of novel photonic devices such as topological insulator lasers. Here, we demonstrate topological lasing of circular polarization in a polymer-cholesteric liquid crystal (P-CLC) superlattice, tunable in the visible wavelength regime. By use of the femtosecond-laser direct-writing and self-assembling techniques, we establish the P-CLC superlattice with a controlled mini-band structure and a topological interface defect, thereby achieving a low threshold for robust topological lasing at about 0.4 uJ. Thanks to the chiral liquid crystal, not only the emission wavelength is thermally tuned, but the circularly polarized lasing is readily achieved. Our results bring about the possibility to realize compact and integrated topological photonic devices at low cost, as well as to engineer an ideal platform for exploring topological physics that involves light-matter interaction in soft-matter environments.