Fano Interference between Localized Plasmons and Interface Reflections
Journal article, 2012
Layers of subwavelength metal nanostructures that support localized surface plasmon resonances are of broad interest in applied nanotechnology, for example, in optical sensor development and solar energy harvesting devices. We measured specular reflection spectra as a function of incidence angle for two-dimensional layers of gold nanodisks on glass and found highly asymmetric line-shapes and a spectral red-shift of up to 0.2 eV, or 10% of the plasmon resonance energy, as the angle changed from normal toward grazing incidence. This dramatic angular dispersion is the result of a tunable Fano interference between the spectrally narrow plasmon emission and a "white" continuum caused by the interface reflection. The data are found to be in excellent agreement with predictions based on a theory for Fresnel reflection coefficients of an interface with subwavelength inclusions. The theory can also be used to derive analytical expressions for the Fano parameters.
Fano resonance
localized surface plasmon
resonances
optical properties
colloidal lithography
gold
light-scattering
index
metamaterials
angular dispersion
nanoparticles
sensitivity
arrays
metamaterial
clusters
Author
Mikael Svedendahl
Chalmers, Applied Physics, Bionanophotonics
Mikael Käll
Chalmers, Applied Physics, Bionanophotonics
ACS Nano
1936-0851 (ISSN) 1936-086X (eISSN)
Vol. 6 8 7533-7539Subject Categories
Chemical Sciences
DOI
10.1021/nn302879j