Anomalous Absorption in Arrays of Metallic Nanoparticles: A Powerful Tool for Quantum Dot Optoelectronics

TL;DR

This paper demonstrates that dense arrays of metallic nanoparticles exhibit magnetic resonances and electromagnetically induced absorption, which can enhance and control the optoelectronic properties of active layers like PbS nanocrystals.

Contribution

It reveals the emergence of magnetic resonances and EIA in dense nanoparticle arrays, enabling new functionalities in quantum dot optoelectronics.

Findings

Magnetic resonances appear in dense nanoparticle arrays.

Spectrally sharp EIA analogues are observed.

Enhanced emission, absorption, and photoconduction in active layers.

Abstract

Periodic arrays of noble metal nanoparticles are emblematic nanostructures in photonics. Their ability to sustain localized surface plasmon resonances has been used throughout the years to demonstrate a variety of passive and active functionalities such as enhanced luminescence in dipolar media and LEDs as well as higher responsivities in photoconductive detectors. Here, we show that additional magnetic resonances, associated with inductive current loops between the nanoparticles and accessible with transverse electric waves, emerge in the limit of dense arrays with subwavelength periods. Moreover, their interplay with the plasmons of the system results in spectrally sharp analogues of electromagnetically induced absorption (EIA). We use these metasurfaces to induce changes and enhancements in the emission, absorption, photoconduction, and polarization properties of active layers of PbS nanocrystals, illustrating the potential of EIA beyond the passive functionalities demonstrated so far in literature.