Diffraction into Propagating and Evanescent Modes from a Single Slit: the Slit-width Dependence

Diffraction from a single slit has been investigated both in the far-field and the near-field. The diffraction in the near-field is dominated by the surface plasmon generation, which shows a striking sinusoidal dependence on the slit-width. In contrast, the far-field transmitted intensity shows linear increase with the slit width.