Measuring the wavelength-dependent divergence of transmission through sub-wavelength hole-arrays by spectral imaging.
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)].
Docter
M W
MW
Young
I T
IT
Piciu
O M
OM
Bossche
A
A
Alkemade
P F
PF
van den Berg
P M
PM
Garini
Y
Y