Loss compensation by spasers in metamaterials

TL;DR

This paper demonstrates that active metamaterials with spasers can achieve complete loss compensation across various pump levels, especially when synchronized externally, redefining the significance of the spasing threshold.

Contribution

It introduces the concept of a loss compensation threshold in spaser-based metamaterials, independent of the spasing threshold, and analyzes the effects of external synchronization.

Findings

Loss compensation is achievable over a wide pump range.

Synchronization removes the difference between below and above spasing threshold.

A new loss compensation threshold is identified, below which compensation is impossible.

Abstract

We show that exact loss compensation can be achieved in active metamaterials containing spasers pumped over a wide range of pumping values both below and above the spasing threshold. We demonstrate that the difference between spaser operation below and above spasing threshold vanishes, when the spaser is synchronized by an external field. As the spasing threshold loses its significance, a new pumping threshold, the threshold of loss compensation, arises. Below this threshold, which is smaller than the spasing threshold, compensation is impossible at any frequency of the external field.