title: Measuring the wavelength-dependent divergence of transmission through sub-wavelength hole-arrays by spectral imaging.
abstract: We present a study on the far-field patterns of light transmitted through sub-wavelength metallic hole-arrays. Spectral imaging measurements are used here on hole arrays for the first time. It provides both spatial and spectral information of the transmission in far-field. The visibility of the images, measured in two illumination modes: Köhler and collimated, is calculated for different planes in and out of focus. The transmission under collimated illumination reveals that 75% of the beam if non-divergent. The results are in agreement with the low divergence measured by Lezec [Science 297, 820 (2002)].
authors.forename: M W
authors.initials: MW
authors.lastname: Docter
authors.forename: I T
authors.initials: IT
authors.lastname: Young
authors.forename: O M
authors.initials: OM
authors.lastname: Piciu
authors.forename: A
authors.initials: A
authors.lastname: Bossche
authors.forename: P F
authors.initials: PF
authors.lastname: Alkemade
authors.forename: P M
authors.initials: PM
authors.lastname: van den Berg
authors.forename: Y
authors.initials: Y
authors.lastname: Garini