We analyze the forces on a small dipolar particle and the electromagnetic momentum density in a configuration consisting in two perpendicular circularly polarized stationary waves. The field distribution shows regions in which the electric and magnetic fields are parallel corresponding to a null Poynting vector. Although the average value of the momentum density, proportional to the Poynting vector, is zero in these regions, there are scattering forces acting on small particles due to light’s spin force. The total scattering force suggests a new definition of the average value of the momentum density for free propagating electromagnetic fields.
© 2012 Optical Society of America
Original Manuscript: May 1, 2012
Revised Manuscript: May 17, 2012
Manuscript Accepted: May 20, 2012
Published: July 3, 2012
Vol. 7, Iss. 9 Virtual Journal for Biomedical Optics
Manuel I. Marqués and Juan José Saénz, "Scattering forces and electromagnetic momentum density in crossed circularly polarized standing waves," Opt. Lett. 37, 2787-2789 (2012)