References of "Denkova, D"
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See detailLateral Magnetic Near-Field Imaging of Plasmonic Nanoantennas With Increasing Complexity
Denkova, D.; Verellen, N.; Silhanek, Alejandro ULg et al

in Small : Nano Micro (2014)

The design of many promising, newly emerging classes of photonic metamaterials and subwavelength confinement structures requires detailed knowledge and understanding of the electromagnetic near-field ... [more ▼]

The design of many promising, newly emerging classes of photonic metamaterials and subwavelength confinement structures requires detailed knowledge and understanding of the electromagnetic near-field interactions between their building blocks. While the electric field distributions and, respectively, the electric interactions of different nanostructures can be routinely measured, for example, by scattering near-field microscopy, only recently experimental methods for imaging the magnetic field distributions became available. In this paper, we provide direct experimental maps of the lateral magnetic near-field distributions of variously shaped plasmonic nanoantennas by using hollow-pyramid aperture scanning near-field optical microscopy (SNOM). We study both simple plasmonic nanoresonators, such as bars, disks, rings and more complex antennas. For the studied structures, the magnetic near-field distributions of the complex resonators have been found to be a superposition of the magnetic near-fields of the individual constituting elements. These experimental results, explained and validated by numerical simulations, open new possibilities for engineering and characterization of complex plasmonic antennas with increased functionality. [less ▲]

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See detailMapping Magnetic Near-Field Distributions of Plasmonic Nanoantennas
Denkova, D; Verellen, N; Silhanek, Alejandro ULg et al

in ACS Nano (2013)

We present direct experimental mapping of the lateral magnetic near-field distribution in plasmonic nanoantennas using aperture scanning nearfield optical microscopy (SNOM). By means of full-field ... [more ▼]

We present direct experimental mapping of the lateral magnetic near-field distribution in plasmonic nanoantennas using aperture scanning nearfield optical microscopy (SNOM). By means of full-field simulations it is demonstrated how the coupling of the hollow-pyramid aperture probe to the nanoantenna induces an effective magnetic dipole which efficiently excites surface plasmon resonances only at lateral magnetic field maxima. This excitation in turn affects the detected light intensity enabling the visualization of the lateral magnetic near-field distribution of multiple odd and even order plasmon modes with subwavelength spatial resolution. [less ▲]

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See detailPlasmon-Enhanced Sub-Wavelength Laser Ablation: Plasmonic Nanojets
Valev, V.K.; Denkova, D.; Zheng, X. et al

in Advanced Materials (2012), 24

Plasmonic hotspots are regions on the surface of metal nanostructures where light causes very strong oscillation of the electrons. Because electron oscillations constitute an electric current and because ... [more ▼]

Plasmonic hotspots are regions on the surface of metal nanostructures where light causes very strong oscillation of the electrons. Because electron oscillations constitute an electric current and because electric currents heat up the material the same way an electric stove heats up in the kitchen, the plasmonic hotspots are extremely hot. So hot that they can melt the gold in a spot much smaller than the wavelength of light. We were successfully able to demonstrate that this tiny little pool of molten gold can give rise to the smallest nanojets ever observed. [less ▲]

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See detailDistributing the Optical Near-Field for Efficient Field-Enhancements in Nanostructures
Valev, V; De Clercq, B; Biris, C et al

in Advanced Materials (2012), 24

Circularly polarized light imparts a sense of rotation on the electron density in ring-shaped gold nanostructures. As a consequence, the near-field enhancement becomes homogeneous on the surface of the ... [more ▼]

Circularly polarized light imparts a sense of rotation on the electron density in ring-shaped gold nanostructures. As a consequence, the near-field enhancement becomes homogeneous on the surface of the nanostructures, thereby increasing the opportunity for interaction with molecules. This type of nanostructured samples can find a broad range of applications in chemical processes where the interaction between molecules and local field enhancements play an important role. [less ▲]

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See detailThe role of chiral local field enhancements below the resolution limit of Second Harmonic Generation microscopy
Valev, V.; Clercq, B.; Zheng, X. et al

in Optics Express (2011), 20(1), 256

While it has been demonstrated that, above its resolution limit, Second Harmonic Generation (SHG) microscopy can map chiral local field enhancements, below that limit, structural defects were found to ... [more ▼]

While it has been demonstrated that, above its resolution limit, Second Harmonic Generation (SHG) microscopy can map chiral local field enhancements, below that limit, structural defects were found to play a major role. Here we show that, even below the resolution limit, the contributions from chiral local field enhancements to the SHG signal can dominate over those by structural defects. We report highly homogeneous SHG micrographs of star-shaped gold nanostructures, where the SHG circular dichroism effect is clearly visible from virtually every single nanostructure. Most likely, size and geometry determine the dominant contributions to the SHG signal in nanostructured systems. [less ▲]

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See detailHotspot Decorations Map Plasmonic Patterns with the Resolution of Scanning Probe Techniques
Valev, V. K.; Silhanek, Alejandro ULg; Jeyaram, Y. et al

in Physical Review Letters (2011), 106(22),

In high definition mapping of the plasmonic patterns on the surfaces of nanostructures, the diffraction limit of light remains an important obstacle. Here we demonstrate that this diffraction limit can be ... [more ▼]

In high definition mapping of the plasmonic patterns on the surfaces of nanostructures, the diffraction limit of light remains an important obstacle. Here we demonstrate that this diffraction limit can be completely circumvented. We show that upon illuminating nanostructures made of nickel and palladium, the resulting surface-plasmon pattern is imprinted on the structures themselves; the hotspots (regions of local field enhancement) are decorated with overgrowths, allowing for their subsequent imaging with scanning-probe techniques. The resulting resolution of plasmon pattern imaging is correspondingly improved. [less ▲]

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