Optical force on a cylindrical cloak under arbitrary wave illumination.

The optical force distribution in the cylindrical cloak under arbitrary incident waves is presented. We show that on the inner surface of the cloak both the induced surface currents and polarization charges interact with the waves and give opposite radiation pressure onto the inner surface. The Lorentz force in the cloak can contribute to change the trajectory of the rays, while in some cases it may only reflect the rays having a tendency to decrease the total energy it carries. The force is symmetric and in balance. Therefore the total momentum transfer from the waves to the cylindrical cloak is zero.