  The existence of resonant enhanced transmission and collimation of light
waves by subwavelength slits in metal films [for example, see T.W. Ebbesen et
al., Nature (London) 391, 667 (1998) and H.J. Lezec et al., Science, 297, 820
(2002)] leads to the basic question: Can a light pulse be enhanced and
simultaneously localized in space and time by a subwavelength slit? To address
this question, the spatial distribution of the energy flux of an ultrashort
(femtosecond) wave-packet diffracted by a subwavelength (nanometer-size) slit
was analyzed by using the conventional approach based on the Neerhoff and Mur
solution of Maxwell's equations. The results show that a light pulse can be
enhanced by orders of magnitude and simultaneously localized in the near-field
diffraction zone at the nm- and fs-scales. Possible applications in
nanophotonics are discussed.
