Persistent response in ultra-strongly driven mechanical membrane resonators

We study experimentally and theoretically the phenomenon of persistent response in ultra-strongly driven membrane resonators. This term denotes the development of a vibrating state with nearly constant amplitude over an extreme wide frequency range. We reveal the underlying mechanism of the persistent response state by directly imaging the vibrational state using advanced optical interferometry. We argue that the persistent state is related to the nonlinear interaction between higher order flexural modes and higher-order overtones of the driven mode. Finally, we propose a stability diagram for the different vibrational states that the membrane can adopt.