Scattering and extinction from high-aspect-ratio trenches

Alexander Sylvester Roberts, Thomas Søndergaard, Manohar Chirumamilla, Anders Lambertus Pors, Jonas Beermann, Kjeld Pedersen, Sergey I. Bozhevolnyi

Research output: Contribution to conference without publisher/journalPosterResearch


We construct a semi-analytical model describing the scattering, extinction and absorption properties of a high aspect-ratio trench in a metallic film. We find that these trenches act as highly efficient scatterers of free waves. In the perfect conductor limit, which for many metals is approached in the long-wavelength regime, the scattering cross section has the maximum value for a dipolar scatterer, which depends exclusively on the wavelength. Numerical simulations are performed to validate model findings and evaluate under which circumstances the model is accurate.
We fabricate tapered high aspect-ratio trenches of various depths into a gold monocrystal, which we characterize by reflection spectroscopy and dark field imaging, confirming their resonantbehavior. Furthermore, we estimate the field enhancement by means of two-photonluminescence.
Original languageEnglish
Publication date19. Nov 2015
Number of pages1
Publication statusPublished - 19. Nov 2015


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