Enhancement of magnonic frequency combs by exceptional points

Frequency combs have high time–frequency accuracy, which makes them useful for applications in precision spectroscopy, ultra-sensitive detection and atomic clocks. Traditional methods of creating frequency combs hinge on material nonlinearities, which are often weak. These methods require high power densities to surpass their initiation thresholds, subsequently limiting their potential use. Here we demonstrate a nonlinear coupling process that efficiently generates magnonic frequency combs by exploiting exceptional points in a coupled system of two different magnon modes. Our approach is a simple and optimal path to produce magnonic frequency combs at low pump power with excellent tunability of exceptional points. Frequency combs, which are important for applications in precision spectroscopy, depend on material nonlinearities for their function, which can be hard to engineer. Now an approach combining magnons and exceptional points is shown to be effective.