Tailoring directional chiral emission from molecules coupled to extrinsic chiral quasi-bound states in the continuum

Year: 2024

Type: article

Abstract: We investigate the chiral emission from non-chiral molecules coupled to metasurfaces with a unit cell formed by dimers of detuned and displaced Si nanodisks. The detuning and displacement lead to the formation of narrow modes, known as quasi-bound states in the continuum (Q-BICs), with different electric and magnetic characteristics. The dispersion and character of the modes are explained by using the guided-mode expansion method and finite-element simulations. The coupling between these modes leads to an extrinsic chiral response with large circular dichroism for defined energies and wavevectors. When the lattice constant of the metasurface is changed, the dispersion of the extrinsic chiral Q-BICs can be tuned and the emission properties of a thin film of dye molecules on top of the metasurface are modified. In particular, we observe strongly directional and circularly polarized emission from the achiral dye molecules with a degree of circular polarization reaching 0.8 at the wavelengths defined by the dispersion of the Q-BICs. These results could enable the realization of compact light sources with a large degree of circular polarization for applications in displays, optical recording, or optical communication.

Source: Photonics Research

DOI: 10.1364/prj.528976

Authors: Minpeng Liang, Lucio Claudio Andreani, Anton Matthijs Berghuis, José Luis Pura, Shunsuke Murai, Hongguang Dong, José A. Sánchez-Gil, Jaime Gómez Rivas

Institutions: University of Pavia, Universidad de Valladolid, Consejo Superior de Investigaciones Científicas, Instituto de Estructura de la Materia, Kyoto University, Zhejiang University

Language: English

Topic: Metamaterials and Metasurfaces Applications

Subfield: Electronic, Optical and Magnetic Materials

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: Ministerio de Ciencia, Innovación y Universidades, European Commission, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, China Scholarship Council, Ministero dell'Università e della Ricerca, Japan Society for the Promotion of Science, European Regional Development Fund, Agencia Estatal de Investigación, HORIZON EUROPE European Innovation Council, NextGenerationEU

OpenAlex ID: W4401636472