Giant Enhancement of Magnonic Frequency Combs by Exceptional Points

TL;DR

This paper demonstrates a highly efficient method for generating magnonic frequency combs by exploiting exceptional points in a coupled system, significantly reducing power requirements and enhancing tunability for advanced applications.

Contribution

It introduces a novel nonlinear process leveraging exceptional points to generate magnonic frequency combs without cavities, improving efficiency and tunability over traditional methods.

Findings

Achieved efficient magnonic frequency comb generation at low pump power.

Enabled tunability of exceptional points via pump polarization and power.

Established a link between non-Hermitian physics and magnonic frequency combs.

Abstract

With their incomparable time-frequency accuracy, frequency combs have significantly advanced precision spectroscopy, ultra-sensitive detection, and atomic clocks. Traditional methods to create photonic, phononic, and magnonic frequency combs hinge on material nonlinearities which are often weak, necessitating high power densities to surpass their initiation thresholds, which subsequently limits their applications. Here, we introduce a novel nonlinear process to efficiently generate magnonic frequency combs (MFCs) by exploiting exceptional points (EPs) in a coupled system comprising a pump-induced magnon mode and a Kittel mode. Even without any cavity, our method greatly improves the efficiency of nonlinear frequency conversion and achieves optimal MFCs at low pump power. Additionally, our novel nonlinear process enables excellent tunability of EPs using the polarization and power of the pump, simplifying MFC generation and manipulation. Our work establishes a synergistic relationship between non-Hermitian physics and MFCs, which is advantages for coherent/quantum information processing and ultra-sensitive detection.