Chiroptical Response Inversion and Enhancement of Room‐Temperature Exciton‐Polaritons Using 2D Chirality in Perovskites

Abstract

Although chiral semiconductors have shown promising progress in direct circularly polarized light (CPL) detection and emission, they still face potential challenges. A chirality‐switching mechanism or approach integrating two enantiomers is needed to discriminate the handedness of a given CPL; additionally, a large material volume is required for sufficient chiroptical interaction. These two requirements pose significant obstacles to the simplification and miniaturization of the devices. Here, w e demonstrate room‐temperature chiral polaritons fulfilling dual‐handedness functions and exhibiting a more‐than‐two‐order enhancement of the chiroptical signal, by embedding a 40‐nm‐thick perovskite film with a two‐dimensional chiroptical effect into a Fabry‐Perot cavity. By mixing chiral perovskites with different crystal structures, w e accomplish a pronounced two‐dimensional chiroptical effect in the perovskite film, featured by an inverted chiroptical response for counter‐propagating CPL. This inversion behavior matches the photonic handedness switch during CPL circulation in the Fabry‐Perot cavity, thus harvesting giant enhancement of the chiroptical response. Furthermore, affected by the unique quarter‐wave‐plate effects, the polariton emission achieves a chiral dissymmetry of ±4% (for the emission from the front and the back sides). The room‐temperature polaritons with the strong dissymmetric chiroptical interaction should have implications on a fundamental level and future on‐chip applications for bio‐molecule analysis and quantum computing.This article is protected by copyright. All rights reserved

Theory predicts 2D chiral polaritons based on achiral Fabry–Pérot cavities using apparent circular dichroism

“…Note added in proof: While this paper was in review, 2D chiral polaritons based on achiral FP cavities using ACD were experimentally reported for perovskite films 82 .…”

Exceptionally High-glum Circularly Polarized Lasers Empowered by Strong 2D-Chiroptical Response in a Host–Guest Supramolecular Microcrystal

“…Therefore, a potent mechanism to generate circular polarization in optical gain media is highly desired, which can be integral for advancing organic CP lasers. Two-dimensional (2D) chirality, 16,17 arising from specific planar chiral configurations that resist complete superimposition with their mirror images through 2D translation or rotation, has found extensive applications in chiral metasurfaces with enhanced chiroptical response, 18,19 holding great promise for high-g lum CP lasers. In addition, the twist of these planar chiral configurations appears reversed for an opposite observation direction (see Scheme 1, top), which may result in an inverted 2D-chiroptical activity.…”