# Driving plasmonic nanoantennas at perfect impedance matching using generalized coherent perfect absorption

## TL;DR

This paper introduces a generalized coherent perfect absorption (gCPA) method for plasmonic nanoantennas, enabling perfect impedance matching and efficient energy absorption by controlling specific plasmonic modes, with applications in sensing.

## Contribution

The paper extends CPA to include radiative losses in plasmonic nanoantennas, demonstrating perfect impedance matching between a nanowire waveguide and a nanoantenna.

## Key findings

- Achieved perfect impedance matching using gCPA.
- Controlled absorption of specific plasmonic modes.
- Potential for background-free sensing applications.

## Abstract

Coherent perfect absorption (CPA) describes the absence of all outgoing modes from a lossy resonator, driven by lossless incoming modes. Here, we show that for nanoresonators that also exhibit radiative losses, e.g. plasmonic nanoantennas, a generalized version of CPA (gCPA) can be applied. In gCPA outgoing modes are sup-pressed only for a subset of (guided plasmonic) modes while other (radiative) modes are treated as additional loss channels - a situation typically referred to as perfect impedance matching. Here we make use of gCPA to show how to achieve perfect impedance matching between a single nanowire plasmonic waveguide and a plasmonic nanoantenna. Antennas with both radiant and subradiant characteristics are considered. We further demonstrate potential applications in background-free sensing.

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Source: https://tomesphere.com/paper/1907.08174