Resonant radiation pressure on neutral particles in a waveguide

A theoretical analysis of electromagnetic forces on neutral particles in a hollow waveguide is presented. We show that the effective scattering cross section of a very small (Rayleigh) particle can be strongly modified inside a waveguide. The coupling or the scattered dipolar field with the waveguid e modes induces a resonant enhanced backscattering state of the scatterer-g uide system close to the onset of new modes. The particle effective cross s ection can then be as large as the wavelength even far from any transition resonance. As we will show, a small particle can be strongly accelerated al ong the guide axis while being highly confined in a narrow zone of the cros s section of the guide.