Spectral magneto-optical tunability using Bragg plasmons

• Magnetoplasmonics is a field where external magnetic fields are utilized to control the optical properties that come from plasmons. Active control of plasmonics has many applications in energy harvesting and nanosensing. [1]We demonstrate experimentally the optical and magnetooptical response from Bragg plasmons [2] using diffraction from magnetoplasmonic nanodisks arranged in a periodic 2D square pattern from the coupled islands. The circular islands are 450 nm in diameter and have a lateral periodicity of 512 nm. This enables diffraction parallel to the surface which in turn yields Bragg plasmon excitation due to the electric field enhancement. The alloy is a combination of Fe and Pd, Fe20Pd80, in order to have a simple material that has both the magnetic functionality as well as the plasmonic.Specular reflectivity and transverse magnetooptical Kerr effect (TMOKE) spectra [3] are compared to show how the optical measurements relate to the magnetooptical enhancement. The experimental data is compared to a simple diffraction model that accounts for the lateral dimensions of the nanostructure and the diffraction which gives the Bragg plasmon onset. In this way we show the link between the Bragg plasmon excitation and the changes in TMOKE asymmetry.[1] Gaspar Armelles and Alexandre Dmitriev, “Focus on magnetoplasmonics”, New J. Phys. 16 045012, 2014[2] Melander et al., “Spectral magnetooptical tunability from Bragg plasmons”, to be submitted[3] Melander et al., “Influence of the magnetic field on the plasmonic properties of transparent Ni anti-dot arrays”, Appl. Phys. Lett. 101, 063107 (2012)

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NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

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