Preparation and Manipulation of Chiral Exciton-Polaritons at Room Temperature
Abstract
Exciton-polaritons are bosonic quasi-particles formed by strong coupling between excitons from an emitter and photons from an optical cavity. Such hybrid excitations have shown promise in diverse applications, ranging from ultrafast switching to selective chemistry to low-threshold lasing. Manipulating the chiral properties of polaritons, however, is underexplored, and especially at room temperature. One challenge in accessing chiral polaritons is that most excitonic materials that are chiral exhibit only weak chirality (if any) at room temperature. Moreover, phonon-induced decoherence greatly hinders intrinsic chirality of emitters; even when integrated into high-quality-factor cavities based on distributed Bragg reflectors or photonic crystals, cryogenic temperatures are required to maintain the chirality of the polaritons. Control over polariton chirality has great potential for display techniques, quantum communication and computation, and sensing with high sensitivity and selectivity. Our work is expected to overcome key challenges byproviding access to nanoscale chiral light sources, efficient pathways to route chiral photons for on-chip optical computing, and prospects for coherent chiral light emission.This proposal aims to prepare and manipulate chiral polaritons at room temperature, spatially and temporally. Plasmonic cavities are known to exhibit ultrafast responses that can overcome phonon-induced decoherence, and open-architecture cavities enable ready integration with active and responsive materials. We propose to combine plasmonic nanoparticle lattices as cavities with inorganic semiconducting nanomaterials as emitters to prepare room-temperature chiral polaritons that we plan to manipulate, transport, and realize coherent emission. Our approach will focus on integrating chiral plasmonic lattice design, chiral material exploration, and characterization tool development. Major scientific outcomes include: (1) models that explain how broken inversion-symmetry of lattices impacts the chirality of cavity resonances and hence polaritons; (2) experimental identification of how polariton chirality influences their propagation; and (3) determination of how chirality evolves temporally during different polariton emission processes. Major product outcomes include: (1) multiple methods to use spin-momentum coupling of cavities to switch on/off chirality of polaritons at room-temperature; (2) approaches to achieve long-range and stable on-chip energy transport using chiral polaritons; (3) low-threshold and on-demand degrees of chirality from polariton emission; and (4) new optical characterization techniques to reveal temporal information of coherence and chirality of polariton emission.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 10, 2025
- Source ID
- N000142512240
Entities
People
- Teri W. Odom
Organizations
- Northwestern University
- Office of Naval Research
- United States Navy