  The Casimir force, originating from vacuum zero-point energy, is one of the
most intriguing purely quantum effects. It has attracted renewed interests in
current field of nanomechanics, due to the rapid size decrease of on-chip
devices. Here we study the optomechanically-induced transparency (OMIT) with a
tunable Casimir force. We find that the optical output rate can be
significantly altered by the vacuum force, even terminated and then restored,
indicating a highly-controlled optical switch. Our result addresses the
possibility of designing exotic optical nano-devices by harnessing the power of
vacuum.
