  The ground state cooling of Brillouin scattering optomechanical system is
limited by defects in practical sample. In this paper, we propose a new
compensatory cooling mechanism for Brillouin scattering optomechanical system
with exceptional points (EPs). By using the EPs both in optical and mechanical
modes, the limited cooling process is compensated effectively. The dual-EPs
system, which is discovered in this work for the first time, can be induced by
two defects with specific relative angles and has function of not only actively
manipulating the coupling strength of optical modes but also the Brillouin
phonon modes. Our results provide new tools to manipulate the optomechanical
interaction in multi-mode systems and open the possibility of quantum state
transfer and quantum interface protocols based on phonon cooling in quantum
applications.
