  Direct detection of phonons is important for the investigation of information
interconversion between the resonantly coupled magnons and phonons. Here we
report resonant coupling of magnons and phonons, which can be directly
visualized by using micro focused Brillouin light scattering in Ni/LiNbO3
hybrid heterostructures. The patterns of surface acoustic wave phonons,
originating from the interference between the original wave {\psi}0(A_0,k) and
reflected wave {\psi}1(A_1,-k), can be modulated by magnetic field due to the
magnon-phonon coupling. By analyzing the information of phonons obtained from
Brillouin spectroscopy, the properties of the magnon system (Ni film), e.g.,
ferromagnetic resonance field and resonance linewidth can be determined. The
results provide spatially resolved information about phonon manipulation and
detection in a coupled magnon-phonon system.
