C. F. Bohren, "How can a particle absorb more than the light incident
  on it?", Am J Phys, 51 #4, pp323  Apr 1983

  ABSTRACT
  A particle can indeed absorb more than the light incident on it. 
  Metallic particles at ultraviolet frequencies are one class of such
  particles, and insulating particles at infrared frequencies are another. 
  In the former, strong absorption is associated with excitation of
  surfaces plasmons; in the latter it is associated with excitation of
  surface phonons.  In both instances, the target area a particle presents
  to incident light can be much greater than its geometrical
  cross-sectional area.  This is strikingly evident from the field lines
  of the Poynting vector in the vicinity of a small sphere illuminated by
  a plane wave. 




  H. Paul and R. Fischer  "Light Absorption by a dipole", SOV. PHYS. USP.,
  26(10)  Oct. 1983  pp 923-926

  ABSTRACT
  In semiclassical radiation theory, the electric dipole moment induced
  on an atom by a strong incident field absorbs much more energy, per sec,
  than is flowing through its geometrical cross section.  This means that
  the atom has the capability to "suck up" electromagnetic energy from a
  spatial region that is by far larger than its own volume.  An intuitive
  understanding of this effect is provided by studying, in the framework
  of classical electrodynamics, the energy flow in the total field made up
  by superposition of the incident wave and the field that is generated by
  the dipole also in the absorptive case.




Also suggested by A. Boswell, regarding small-antenna physics:

  Chu, J.Appl.Phys. Dec. 1948 

  Hansen, Proc.IEEE Feb. 1981