  We present a novel mechanism for generating a wide bandwidth squeezed optical
output field in an opto-magnomechanical system. In this system, the magnon
(mechanical) mode in the yttrium-iron-garnet crystal is coupled to the
microwave field (optical field) through magnetic dipole (radiation pressure)
interaction. The magnetostrictive force induced by the yttrium-iron-garnet
crystal causes a mechanical displacement and creates a quadrature squeezed
magnon mode. Eventually, this quadrature squeezed mechanical mode is
transferred to the output optical field through state-swap interaction. Our
results demonstrate the optimal parameter range for obtaining a stable squeezed
optical output field with a wide bandwidth. Moreover, the squeezed light field
exhibits strong robustness to environmental temperature. The new scheme we
propose has potential applications in quantum precision measurements, quantum
wireless networks, quantum radar, etc.
