Few-layer hyperbolic multilayer for spontaneous emission enhancement

TL;DR

This paper demonstrates that ultrathin multilayer hyperbolic metamaterials with fewer layers can outperform traditional thicker structures in enhancing spontaneous emission, due to improved plasmonic coupling and reflection properties.

Contribution

It reveals that fewer, thinner layers in hyperbolic metamaterials can achieve superior Purcell effect, challenging the conventional requirement of many layers for emission enhancement.

Findings

Fewer layers outperform in Purcell effect compared to traditional multilayers.

Negative contributions from increased layers reduce the imaginary part of reflection.

Thinner metal layers strengthen surface plasmon polariton coupling.

Abstract

Multilayer hyperbolic metamaterials consisting of alternating metal and dielectric layers have important applications in spontaneous emission enhancement. In contrast to the conventional choice of at least dozens of layers in multilayer structures to achieve tunable Purcell effect on quantum emitters, our numerical calculations reveal that multilayers with fewer layers and thinner layers would outperform in Purcell effect. These discoveries are attributed to the negative contributions by an increasing layer number to the imaginary part of the reflection coefficient, and the stronger coupling between surface plasmon polariton modes on a thinner metal layer. This work could provide fundamental insights and practical guide for optimizing the local density of optical states enhancement functionality of ultrathin and even two-dimensional photon sources.