Publications by authors named "R A Lukaszew"

Vanadium dioxide (VO) is one of the most extensively studied materials in the strongly correlated electron family capable of sustaining an insulator-to-metal transition. Here we present our studies of high-quality thin films of epitaxially grown VO on c-AlO(0001) and TiO(001) via reactive DC pulsed magnetron sputtering. We present the structural transition probed via Reflection High Energy Electron Diffraction (RHEED) for the first time and we correlate the surface microstructure measurements with simulations before, during, and after the thermally induced transition.

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We report on a new mechanism capable of inducing the insulator-metal transition (IMT) in VO via surface plasmon polaritons (SPP). Our theoretical model predicts that for a bilayer Au-VO sample an enhanced electromagnetic energy density at the Au-VO interface will occur at 1064nm laser wavelength when SPPs are excited in the Au layer. This effect can assist the IMT in the VO layer and at the same time, the SPP absorption can be used to detect it.

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Metallic gratings can support Fano resonances when illuminated with EM radiation, and their characteristic reflectivity versus incident angle lineshape can be greatly affected by the surrounding dielectric environment and the grating geometry. By using conformal oblique incidence thin film deposition onto an optical grating substrate, it is possible to increase the grating amplitude due to shadowing effects, thereby enabling tailoring of the damping processes and electromagnetic field couplings of the Fano resonances, hence optimizing the associated localized electric field intensity. To investigate these effects we compare the optical reflectivity under resonance excitation in samples prepared by oblique angle deposition (OAD) and under normal deposition (ND) onto the same patterned surfaces.

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Correlated experimental and simulation studies on the modulation of Surface Plasmon Polaritons (SPP) in Au/VO2 bilayers are presented. The modification of the SPP wave vector by the thermally-induced insulator-to-metal phase transition (IMT) in VO2 was investigated by measuring the optical reflectivity of the sample. Reflectivity changes are observed for VO2 when transitioning between the insulating and metallic states, enabling modulation of the SPP in the Au layer by the thermally induced IMT in the VO2 layer.

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We report on the first observation of optically excited surface plasmon polaritons (SPPs) in the conducting phase of vanadium dioxide (VO(2)) thin films. VO(2) is low-loss optical material that undergoes an insulator-metal transition (IMT) under suitable thermal, optical, or electrical stimulation, thus enabling tunable SPP excitation of the conducting phase. Here we applied IR light (1520 nm) to excite SPPs while thermally inducing the IMT by changing the VO(2) temperature, and observed a clear trend from nonabsorption in the insulator phase to high absorption in the conducting phase due to SPP excitation in the latter phase.

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