A passive acoustic sensor that may be employed to detect sounds emanating
from under the surface of a body of water. The sensor uses optics to
determine vibration on the surface of a water body to detect sound
pressure waves from underwater sound sources. The sensor is deployed
above the surface and has no direct interaction with anything under the
surface that may be emanating sounds. This allows the invention to
operate without interfering with potential sound sources as well as
allows for numerous deployment methods.