Total absorption of an electromagnetic wave by an overdense plasma
  We show both theoretically and experimentally that an electromagnetic wave can be totally absorbed by an overdense plasma when a subwavelength diffraction grating is placed in front of the plasma surface. The absorption is due to dissipation of surface plasma waves (plasmons-polaritons) that have been resonantly excited by the evanescent component of the diffracted electromagnetic wave. The developed theoretical model allows one to determine the conditions for the total absorption. 
Yury P. Bliokh, Joshua Felsteiner, and Yakov Z. Slutsker