RESUMO
We present correlated experimental and theoretical studies on the magnetic field modulation of Surface Plasmon Polaritons (SPPs) in Au/Co/Au trilayers. The trilayers were grown by sputter deposition on glass slides with the Co films placed at different distances from the surface and with different thickness. We show that it is possible to tailor Au/Co/Au trilayers with the critical thickness needed for optimum excitation of SPPs leading to large localized electromagnetic fields. The modification of the SPP wave vector by externally applied magnetic fields was investigated by measuring the magneto-optical activity in transverse configuration. In addition, using magneto-optics as a tool we determined the spatial distribution of the SPP generated electromagnetic fields within Au/Co/Au samples by analyzing the field-dependent optical response, demonstrating that it is possible to excite SPPs that exhibit large electromagnetic fields that are also magneto-optically active and therefore can be modulated by externally applied magnetic fields.
RESUMO
The propagation of surface plasmon polaritons (SPPs) on gratings can be experimentally modified when magneto-optically active materials are used. We have observed this effect in Au-Co thin-film bilayers where a polymer grating was patterned on the upper surface. In addition, Au-Co-Au trilayers were grown on polycarbonate gratings, and the Co layer thicknesses and placement from the upper interface were varied to further investigate this effect. We show that the Co layer must be tailored to balance optical absorption and magneto-optical activity, while the pitch of the grating can be adjusted to tune the angular dependence of the field-dependent SPP excitation.
RESUMO
We demonstrate the electro-thermal control of aluminum-doped zinc oxide (Al:ZnO) /vanadium dioxide (VO2) multilayered thin films, where the application of a small electric field enables precise control of the applied heat to the VO2 thin film to induce its semiconductor-metal transition (SMT). The transparent conducting oxide nature of the top Al:ZnO film can be tuned to facilitate the fine control of the SMT of the VO2 thin film and its associated properties. In addition, the Al:ZnO film provides a capping layer to the VO2 thin film, which inhibits oxidation to a more energetically favorable and stable V2O5 phase. It also decreases the SMT of the VO2 thin film by approximately 5-10 °C because of an additional stress induced on the VO2 thin film and/or an alteration of the oxygen vacancy concentration in the VO2 thin film. These results have significant impacts on technological applications for both passive and active devices by exploiting this near-room-temperature SMT.
RESUMO
Plasmonic materials (PMs), featuring large static or dynamic tunability, have significant impact on the optical properties due to their potential for applications in transformation optics, telecommunications, energy, and biomedical areas. Among PMs, the carrier concentration and mobility are two tunable parameters, which control the plasma frequency of a metal. Here, we report on large static and dynamic tunability in wavelengths up to 640â nm in Al-doped ZnO based transparent conducting degenerate semiconductors by controlling both thickness and applied voltages. This extreme tunability is ascribed to an increase in carrier concentration with increasing thickness as well as voltage-induced thermal effects that eventually diminish the carrier concentration and mobility due to complex chemical transformations in the multilayer growth process. These observations could pave the way for optical manipulation of this class of materials for potential transformative applications.