Speckle correlation functions applied to surface plasmons
Frerik van BeijnumJeroen Sirre
Chris Rétif (AMOLF)Martin van Exter
What is a speckle correlation function?
λ=532 nm, C=1 λ=633 nm, C=0
Averaged change of speckle pattern as a function of
wavelength or angle
The traditional speckle correlation function
3D medium: slab of strongly scattering particles
PRL 64, 2788 (1990)
The traditional speckle correlation function
3D medium: slab of strongly scattering particles
PRL 64, 2788 (1990)
Compared to the complexity of the disorder the correlation
function is simple
A surface plasmon polariton (SPP)
Image from: Nature 424, 824 (2004)
Surface wave
Suffers from absorption, propagates typically 10-50
µm
Subwavelength holes excite surface plasmons
Surface plasmons in ordered systems
- holes excite surface plasmons- direct transmission- More than ten years of research to understand and apply extraordinary optical transmission
Nature 391, 667 (1998)
Surface plasmons in ordered systems
- holes excite surface plasmons- direct transmission- More than ten years of research to understand and apply extraordinary optical transmission
Nature 391, 667 (1998)
Compared to the simplicity of the structure the understanding the
transmission spectrum is complicated
How to apply correlation functions to surface plasmons?
Interesting and new:
two transmission processes, direct (black) and surface plasmon assisted (red)
Are speckles seen in transmission?
Very faint speckle pattern
Intensity normalized to peak transmissionOL 36, 3666 (2011)
Correlation width can be separatedin scattering and absorption
Scattering reduces the propagation length by a factor 5
Measured cross section is roughly a fifth of the hole diameter
Absorption agrees with theory
The plasmon contribution vanishes at low density
One parameter fit describes data
Last data point deviates again.
Deviations from model are expected at high densities (hole per squared wavelength).
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