The existence of resonant enhanced transmission and the collimation of light waves by subwavelength slits in metal films [for example, see Ebbesen et al., Nature (London) 391, 667 (1998) and 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.

• Received 9 February 2004

DOI:https://doi.org/10.1103/PhysRevB.70.195428