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Directional radiation of Babinet-inverted optical nanoantenna integrated with plasmonic waveguide.

Kim J, Roh YG, Cheon S, Kim UJ, Hwang SW, Park Y, Lee CW - Sci Rep (2015)

Bottom Line: The coupling efficiency of the integrated nanoantenna is calculated as being approximately 19% using a three-dimensional finite-difference time-domain (3D FDTD) simulation.We also determine, both theoretically and experimentally, that groove depth plays a significant role to function groove structure as a reflector or a director.The demonstrated Babinet-inverted optical nanoantenna integrated with a plasmonic waveguide can be used as a "plasmonic via" in plasmonic nanocircuits.

View Article: PubMed Central - PubMed

Affiliation: Samsung Advanced Institute of Technology, 130, Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 443-803, Korea.

ABSTRACT
We present a Babinet-inverted optical nanoantenna integrated with a plasmonic waveguide. Using an integrated nanoantenna, we can couple the plasmon guide mode in a metal-insulator-metal (MIM) structure into the resonant antenna feed directly. The resonantly excited feed slot then radiates to free space and generates a magnetic dipole-like far-field pattern. The coupling efficiency of the integrated nanoantenna is calculated as being approximately 19% using a three-dimensional finite-difference time-domain (3D FDTD) simulation. By adding an auxiliary groove structure along with the feed, the radiation direction can be controlled similar to an optical Yagi-Uda antenna. We also determine, both theoretically and experimentally, that groove depth plays a significant role to function groove structure as a reflector or a director. The demonstrated Babinet-inverted optical nanoantenna integrated with a plasmonic waveguide can be used as a "plasmonic via" in plasmonic nanocircuits.

No MeSH data available.


Related in: MedlinePlus

Model configurations for near-to-far-field transformations and matrix map of simulated far-field pattern.(a) Geometrical configurations of near-to-far-field transformation simulation. The hemisphere is cut by the x-z (vertical) and x-y (lateral) plane and each cutting plane corresponds to a θ- and ϕ-distribution of the far-field radiation. The structure composed of a single slot and groove is located at the origin of the hemisphere. The groove structure length is labeled L and the distance between the feed and groove is fixed as 100 nm. (b) Far-field radiation pattern calculated from near-to-far field transformation. (c) θ-distribution of simulated far-field radiation. (d) ϕ-distribution of simulated far-field radiation. The red box represents the role change (from weak director to reflector as the length increases) of the groove, depending on its length at fixed depth. The blue box represents the role change (from director to reflector as depth increases) of the groove, depending on its depth at fixed length.
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f4: Model configurations for near-to-far-field transformations and matrix map of simulated far-field pattern.(a) Geometrical configurations of near-to-far-field transformation simulation. The hemisphere is cut by the x-z (vertical) and x-y (lateral) plane and each cutting plane corresponds to a θ- and ϕ-distribution of the far-field radiation. The structure composed of a single slot and groove is located at the origin of the hemisphere. The groove structure length is labeled L and the distance between the feed and groove is fixed as 100 nm. (b) Far-field radiation pattern calculated from near-to-far field transformation. (c) θ-distribution of simulated far-field radiation. (d) ϕ-distribution of simulated far-field radiation. The red box represents the role change (from weak director to reflector as the length increases) of the groove, depending on its length at fixed depth. The blue box represents the role change (from director to reflector as depth increases) of the groove, depending on its depth at fixed length.

Mentions: We considered two geometric parameters of the groove structure, length and depth as a controlled parameter because the effect of the distance from the previous work turns out to be smaller16. Therefore, we fixed the distance between the feed and the auxiliary element as 100 nm during the simulation. The feed length was fixed at 180 nm, resonant to the wavelength of 664 nm (Fig. 4(a)) and we changed the groove length (L) from 180 to 220 nm in 20-nm increments, and the groove depth (δ) from 50 to 200 nm in 50–nm steps. In total, 12 groove condition setups were simulated and evaluated. To determine the appropriate reflector and director conditions at the resonance frequency, a near-to-far-field transformation method was used and far-field radiation patterns for each condition were visualized in table form. The far-field radiation pattern was obtained by evaluating the total fields by 1 m away from the point, where the antenna and the source were located. By projecting the three-dimensional field distribution on the hemi-sphere into a two-dimensional circle plane, we obtained the far-field radiation pattern shown in Fig. 4(b). For the Yagi-Uda antenna, an auxiliary element shorter than that of the feed works as a director, while an auxiliary element longer than the feed generally functions as a reflector2627. Given a fixed groove depth (δ) with 100 nm, we see this trend in the calculated results (red box in Fig. 4(b–d)). Additionally, we also found that the shallow-depth grooves can also play the role of directors, even in long-length conditions since, as the groove depth increases, the groove changes from functioning as a director to a reflector (blue box in Fig. 4(b–d)). To see this effect more clearly, radiation patterns of θ-distribution (cut by the x-z plane) and ϕ-distribution (cut by the x-y plane) are shown in Fig. 4(c,d) respectively.


Directional radiation of Babinet-inverted optical nanoantenna integrated with plasmonic waveguide.

Kim J, Roh YG, Cheon S, Kim UJ, Hwang SW, Park Y, Lee CW - Sci Rep (2015)

Model configurations for near-to-far-field transformations and matrix map of simulated far-field pattern.(a) Geometrical configurations of near-to-far-field transformation simulation. The hemisphere is cut by the x-z (vertical) and x-y (lateral) plane and each cutting plane corresponds to a θ- and ϕ-distribution of the far-field radiation. The structure composed of a single slot and groove is located at the origin of the hemisphere. The groove structure length is labeled L and the distance between the feed and groove is fixed as 100 nm. (b) Far-field radiation pattern calculated from near-to-far field transformation. (c) θ-distribution of simulated far-field radiation. (d) ϕ-distribution of simulated far-field radiation. The red box represents the role change (from weak director to reflector as the length increases) of the groove, depending on its length at fixed depth. The blue box represents the role change (from director to reflector as depth increases) of the groove, depending on its depth at fixed length.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4488836&req=5

f4: Model configurations for near-to-far-field transformations and matrix map of simulated far-field pattern.(a) Geometrical configurations of near-to-far-field transformation simulation. The hemisphere is cut by the x-z (vertical) and x-y (lateral) plane and each cutting plane corresponds to a θ- and ϕ-distribution of the far-field radiation. The structure composed of a single slot and groove is located at the origin of the hemisphere. The groove structure length is labeled L and the distance between the feed and groove is fixed as 100 nm. (b) Far-field radiation pattern calculated from near-to-far field transformation. (c) θ-distribution of simulated far-field radiation. (d) ϕ-distribution of simulated far-field radiation. The red box represents the role change (from weak director to reflector as the length increases) of the groove, depending on its length at fixed depth. The blue box represents the role change (from director to reflector as depth increases) of the groove, depending on its depth at fixed length.
Mentions: We considered two geometric parameters of the groove structure, length and depth as a controlled parameter because the effect of the distance from the previous work turns out to be smaller16. Therefore, we fixed the distance between the feed and the auxiliary element as 100 nm during the simulation. The feed length was fixed at 180 nm, resonant to the wavelength of 664 nm (Fig. 4(a)) and we changed the groove length (L) from 180 to 220 nm in 20-nm increments, and the groove depth (δ) from 50 to 200 nm in 50–nm steps. In total, 12 groove condition setups were simulated and evaluated. To determine the appropriate reflector and director conditions at the resonance frequency, a near-to-far-field transformation method was used and far-field radiation patterns for each condition were visualized in table form. The far-field radiation pattern was obtained by evaluating the total fields by 1 m away from the point, where the antenna and the source were located. By projecting the three-dimensional field distribution on the hemi-sphere into a two-dimensional circle plane, we obtained the far-field radiation pattern shown in Fig. 4(b). For the Yagi-Uda antenna, an auxiliary element shorter than that of the feed works as a director, while an auxiliary element longer than the feed generally functions as a reflector2627. Given a fixed groove depth (δ) with 100 nm, we see this trend in the calculated results (red box in Fig. 4(b–d)). Additionally, we also found that the shallow-depth grooves can also play the role of directors, even in long-length conditions since, as the groove depth increases, the groove changes from functioning as a director to a reflector (blue box in Fig. 4(b–d)). To see this effect more clearly, radiation patterns of θ-distribution (cut by the x-z plane) and ϕ-distribution (cut by the x-y plane) are shown in Fig. 4(c,d) respectively.

Bottom Line: The coupling efficiency of the integrated nanoantenna is calculated as being approximately 19% using a three-dimensional finite-difference time-domain (3D FDTD) simulation.We also determine, both theoretically and experimentally, that groove depth plays a significant role to function groove structure as a reflector or a director.The demonstrated Babinet-inverted optical nanoantenna integrated with a plasmonic waveguide can be used as a "plasmonic via" in plasmonic nanocircuits.

View Article: PubMed Central - PubMed

Affiliation: Samsung Advanced Institute of Technology, 130, Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 443-803, Korea.

ABSTRACT
We present a Babinet-inverted optical nanoantenna integrated with a plasmonic waveguide. Using an integrated nanoantenna, we can couple the plasmon guide mode in a metal-insulator-metal (MIM) structure into the resonant antenna feed directly. The resonantly excited feed slot then radiates to free space and generates a magnetic dipole-like far-field pattern. The coupling efficiency of the integrated nanoantenna is calculated as being approximately 19% using a three-dimensional finite-difference time-domain (3D FDTD) simulation. By adding an auxiliary groove structure along with the feed, the radiation direction can be controlled similar to an optical Yagi-Uda antenna. We also determine, both theoretically and experimentally, that groove depth plays a significant role to function groove structure as a reflector or a director. The demonstrated Babinet-inverted optical nanoantenna integrated with a plasmonic waveguide can be used as a "plasmonic via" in plasmonic nanocircuits.

No MeSH data available.


Related in: MedlinePlus