Cooperative Ordering in Lattices of Interacting Two-Level Dipoles

TL;DR

This study explores how regular monolayers of driven two-level dipoles exhibit cooperative electromagnetic responses, revealing interference effects, mode interactions, and unique ordering phenomena in specific lattice geometries like kagome.

Contribution

It demonstrates the complex cooperative behavior and mode interference in two-level dipole lattices, highlighting the role of lattice geometry and long-range interactions.

Findings

Interference of cooperative eigenmodes modifies dipolar response.

Kagome lattice exhibits simultaneous excitation of subradiant and superradiant modes.

Long-range interactions induce ferroelectric and antiferroelectric ordering.

Abstract

We investigate the cooperative behavior of regular monolayers of driven two-level dipoles, using classical electrodynamics simulations. The dipolar response results from the interference of many cooperative eigenmodes, each frequency-shifted from the single resonant dipole case, and with a modified lifetime, due to the interactions between dipoles. Of particular interest is the kagome lattice, where the semiregular geometry permits simultaneous excitation of two dominant modes, one strongly subradiant, leading to an electromagnetically-induced-transparency-like interference in a two-level system. The interfering modes are associated with ferroelectric and antiferroelectric ordering in alternate lattice rows with long range interactions.