Losses in plasmonics: from mitigating energy dissipation to embracing loss-enabled functionalities

TL;DR

This paper reviews the origins of plasmonic losses and explores strategies to mitigate them or harness them for new functionalities, highlighting hybrid devices and thermoplasmonics applications.

Contribution

It provides a comprehensive overview of loss mitigation techniques and introduces loss-enabled applications, emphasizing hybrid photonic-plasmonic devices and thermoplasmonics.

Findings

Hybrid photonic-plasmonic devices reduce losses and enable cooling.

Thermoplasmonics enables new functionalities like heat-assisted magnetic recording.

Strategies to minimize radiative and dissipative losses are effective in plasmonics.

Abstract

Unlike conventional optics, plasmonics enables unrivalled concentration of optical energy well beyond the diffraction limit of light. However, a significant part of this energy is dissipated as heat. Plasmonic losses present a major hurdle in the development of plasmonic devices and circuits that can compete with other mature technologies. Until recently, they have largely kept the use of plasmonics to a few niche areas where loss is not a key factor, such as surface enhanced Raman scattering and biochemical sensing. Here, we discuss the origin of plasmonic losses and various approaches to either minimize or mitigate them based on understanding of fundamental processes underlying surface plasmon modes excitation and decay. Along with the ongoing effort to find and synthesize better plasmonic materials, optical designs that modify the optical powerflow through plasmonic nanostructures can help in reducing both radiative damping and dissipative losses of surface plasmons. Another strategy relies on the development of hybrid photonic-plasmonic devices by coupling plasmonic nanostructures to resonant optical elements. Hybrid integration not only helps to reduce dissipative losses and radiative damping of surface plasmons, but also makes possible passive radiative cooling of nano-devices. Finally, we review emerging applications of thermoplasmonics that leverage Ohmic losses to achieve new enhanced functionalities. The most successful commercialized example of a loss-enabled novel application of plasmonics is heat-assisted magnetic recording. Other promising technological directions include thermal emission manipulation, cancer therapy, nanofabrication, nano-manipulation, plasmon-enabled material spectroscopy and thermo-catalysis, and solar water treatment.