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3D optical Yagi-Uda nanoantenna array.

Dregely D, Taubert R, Dorfmüller J, Vogelgesang R, Kern K, Giessen H - Nat Commun (2011)

Bottom Line: We show that the concepts of radiofrequency antenna arrays can be applied to the optical regime proving superior directional properties compared with a single planar optical antenna, particularly for emission and reception into the third dimension.Measuring the optical properties of the structure reveals that impinging light on the array is efficiently absorbed on the subwavelength scale because of the high directivity.Moreover, we show in simulations that combining the array with suitable feeding circuits gives rise to the prospect of beam steering at optical wavelengths.

View Article: PubMed Central - PubMed

Affiliation: 4th Physics Institute and Research Center SCoPE, University of Stuttgart, D-70569 Stuttgart, Germany.

No MeSH data available.


Phased array of optical Yagi–Uda antennas.(a) Schematic representation of a 3×3 Yagi–Uda antenna array that is fed by a phase modulating feeding circuit through plasmonic waveguides. A phase difference of the incoming light signal is induced by phase shifters. The direction of the emitted light cone depends on the phase difference between adjacent antennas. (b) Numerical three-dimensional directivity plots of the 3×3 phased array. The beam is scanned in the xz plane from approximately −30° to +30°. This is obtained by inducing a phase shift of Δφ=+2π/3 and Δφ=−2π/3 in the x-direction. The radiation patterns show different peak directivities as the antennas are fed at one end of the feed elements.
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f5: Phased array of optical Yagi–Uda antennas.(a) Schematic representation of a 3×3 Yagi–Uda antenna array that is fed by a phase modulating feeding circuit through plasmonic waveguides. A phase difference of the incoming light signal is induced by phase shifters. The direction of the emitted light cone depends on the phase difference between adjacent antennas. (b) Numerical three-dimensional directivity plots of the 3×3 phased array. The beam is scanned in the xz plane from approximately −30° to +30°. This is obtained by inducing a phase shift of Δφ=+2π/3 and Δφ=−2π/3 in the x-direction. The radiation patterns show different peak directivities as the antennas are fed at one end of the feed elements.

Mentions: In a phased array, each element is driven independently with a defined phase and amplitude. The angular pattern depends on the phase shift between the elements. The concept has been applied for antenna structures in the far infrared, using an array of λ/2 dipole antennas23. We propose to use the optical 3D Yagi–Uda antenna array for beam steering applications in the optical regime at λ=1500 nm. Because of the high directivity of the array, light can be efficiently directed out of the substrate into a well-defined direction. Figure 5a depicts a schematic view of a 3×3 Yagi–Uda antenna array in which the feed elements are connected to plasmonic waveguides24 or high-index dielectric waveguides to avoid major losses in the waveguides25. Each Yagi–Uda antenna is addressed independently and the phase of the feeding circuit is controlled by phase modulators. Inducing a phase shift in the x-direction between adjacent Yagi–Uda antennas of +2π/3 and −2π/3, leads to a beam steering in the xz plane from approximately −30° to +30°, as it is calculated in Figure 5b. The slight asymmetry in the values of the peak directivity of the two patterns occurs as the antennas are fed by the waveguides to the left side of the feed elements as it is shown in Figure 5a.


3D optical Yagi-Uda nanoantenna array.

Dregely D, Taubert R, Dorfmüller J, Vogelgesang R, Kern K, Giessen H - Nat Commun (2011)

Phased array of optical Yagi–Uda antennas.(a) Schematic representation of a 3×3 Yagi–Uda antenna array that is fed by a phase modulating feeding circuit through plasmonic waveguides. A phase difference of the incoming light signal is induced by phase shifters. The direction of the emitted light cone depends on the phase difference between adjacent antennas. (b) Numerical three-dimensional directivity plots of the 3×3 phased array. The beam is scanned in the xz plane from approximately −30° to +30°. This is obtained by inducing a phase shift of Δφ=+2π/3 and Δφ=−2π/3 in the x-direction. The radiation patterns show different peak directivities as the antennas are fed at one end of the feed elements.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3104549&req=5

f5: Phased array of optical Yagi–Uda antennas.(a) Schematic representation of a 3×3 Yagi–Uda antenna array that is fed by a phase modulating feeding circuit through plasmonic waveguides. A phase difference of the incoming light signal is induced by phase shifters. The direction of the emitted light cone depends on the phase difference between adjacent antennas. (b) Numerical three-dimensional directivity plots of the 3×3 phased array. The beam is scanned in the xz plane from approximately −30° to +30°. This is obtained by inducing a phase shift of Δφ=+2π/3 and Δφ=−2π/3 in the x-direction. The radiation patterns show different peak directivities as the antennas are fed at one end of the feed elements.
Mentions: In a phased array, each element is driven independently with a defined phase and amplitude. The angular pattern depends on the phase shift between the elements. The concept has been applied for antenna structures in the far infrared, using an array of λ/2 dipole antennas23. We propose to use the optical 3D Yagi–Uda antenna array for beam steering applications in the optical regime at λ=1500 nm. Because of the high directivity of the array, light can be efficiently directed out of the substrate into a well-defined direction. Figure 5a depicts a schematic view of a 3×3 Yagi–Uda antenna array in which the feed elements are connected to plasmonic waveguides24 or high-index dielectric waveguides to avoid major losses in the waveguides25. Each Yagi–Uda antenna is addressed independently and the phase of the feeding circuit is controlled by phase modulators. Inducing a phase shift in the x-direction between adjacent Yagi–Uda antennas of +2π/3 and −2π/3, leads to a beam steering in the xz plane from approximately −30° to +30°, as it is calculated in Figure 5b. The slight asymmetry in the values of the peak directivity of the two patterns occurs as the antennas are fed by the waveguides to the left side of the feed elements as it is shown in Figure 5a.

Bottom Line: We show that the concepts of radiofrequency antenna arrays can be applied to the optical regime proving superior directional properties compared with a single planar optical antenna, particularly for emission and reception into the third dimension.Measuring the optical properties of the structure reveals that impinging light on the array is efficiently absorbed on the subwavelength scale because of the high directivity.Moreover, we show in simulations that combining the array with suitable feeding circuits gives rise to the prospect of beam steering at optical wavelengths.

View Article: PubMed Central - PubMed

Affiliation: 4th Physics Institute and Research Center SCoPE, University of Stuttgart, D-70569 Stuttgart, Germany.

No MeSH data available.