  Cavity magnomechanics (CMM) is an emerging field and has received much
attention in the past decade. It deals with coherent couplings among microwave
cavity photons, magnons and vibration phonons. So far, all previous CMM
experiments have been operated in the weak-coupling regime. This considerably
limits prospective various applications of the system. Here, we demonstrate the
CMM system in the strong-coupling regime and observe the associated normal-mode
splitting. In this regime, the mechanical oscillator is strongly coupled to a
cavity-magnon polariton that is formed by strongly coupled cavity photons and
magnons, and the polariton-mechanics cooperativity reaches $4\times10^3$, which
is improved by three orders of magnitude than previous CMM experiments. The
system is then in the triple-strong-coupling regime and the normal modes of the
system are the hybridization of microwave photons, magnons and phonons. This is
achieved by significantly reducing the decay rate of the polariton mode using
coherent perfect absorption and the decay rate is reduced by four orders of
magnitude. The work paves the way towards coherent control and measurement of
the quantum states of phonons, photons and magnons, and provides a new platform
for the study of rich strong-coupling effects in multipartite hybrid systems.
