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Bias field tailored plasmonic nano-electrode for high-power terahertz photonic devices.

Moon K, Lee IM, Shin JH, Lee ES, Kim N, Lee WH, Ko H, Han SP, Park KH - Sci Rep (2015)

Bottom Line: Photoconductive antennas with nano-structured electrodes and which show significantly improved performances have been proposed to satisfy the demand for compact and efficient terahertz (THz) sources.Plasmonic field enhancement was previously considered the dominant mechanism accounting for the improvements in the underlying physics.Our findings will pave the way for new perspectives in the design and analysis of plasmonic nano-structures for more efficient THz photonic devices.

View Article: PubMed Central - PubMed

Affiliation: THz Photonics Creative Research Center, Future Research Creative Laboratory, Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-700, Korea.

ABSTRACT
Photoconductive antennas with nano-structured electrodes and which show significantly improved performances have been proposed to satisfy the demand for compact and efficient terahertz (THz) sources. Plasmonic field enhancement was previously considered the dominant mechanism accounting for the improvements in the underlying physics. However, we discovered that the role of plasmonic field enhancement is limited and near-field distribution of bias field should be considered as well. In this paper, we clearly show that the locally enhanced bias field due to the size effect is much more important than the plasmonic enhanced absorption in the nano-structured electrodes for the THz emitters. Consequently, an improved nano-electrode design is presented by tailoring bias field distribution and plasmonic enhancement. Our findings will pave the way for new perspectives in the design and analysis of plasmonic nano-structures for more efficient THz photonic devices.

No MeSH data available.


Related in: MedlinePlus

THz emission from the large-aperture PCAs: (a) Time-domain curves. (b) FFT spectra. (c) Absolute power and optical-to-THz conversion efficiency measured as a function of the optical excitation power.
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f5: THz emission from the large-aperture PCAs: (a) Time-domain curves. (b) FFT spectra. (c) Absolute power and optical-to-THz conversion efficiency measured as a function of the optical excitation power.

Mentions: At one extent of these two possibilities, we fabricated nano-electrodes on large-aperture emitters to experimentally confirm the expected enhancement in the low optical power density. For the comparison, we also fabricated a reference large-aperture PCA (L-PCA) without nano-electrodes. The active areas of all the L-PCAs were set to 300 × 300 μm2, identical to the size of a commercial large-aperture emitter34, which approximately reduces the optical power density to 1/280. The structure and optical microscope image of the SNG-based large-aperture emitter are shown in Fig. 4(a,b), respectively. (Detailed fabrication procedures are given in the methods.) We measured the time-domain curves from the large-aperture emitters, then replaced the receiver with a calibrated commercial pyro-electric detector (THz5I-BL-BNC, Gentec-EO) for absolute power measurements. The results obtained are illustrated in Fig. 5(a–c).


Bias field tailored plasmonic nano-electrode for high-power terahertz photonic devices.

Moon K, Lee IM, Shin JH, Lee ES, Kim N, Lee WH, Ko H, Han SP, Park KH - Sci Rep (2015)

THz emission from the large-aperture PCAs: (a) Time-domain curves. (b) FFT spectra. (c) Absolute power and optical-to-THz conversion efficiency measured as a function of the optical excitation power.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561887&req=5

f5: THz emission from the large-aperture PCAs: (a) Time-domain curves. (b) FFT spectra. (c) Absolute power and optical-to-THz conversion efficiency measured as a function of the optical excitation power.
Mentions: At one extent of these two possibilities, we fabricated nano-electrodes on large-aperture emitters to experimentally confirm the expected enhancement in the low optical power density. For the comparison, we also fabricated a reference large-aperture PCA (L-PCA) without nano-electrodes. The active areas of all the L-PCAs were set to 300 × 300 μm2, identical to the size of a commercial large-aperture emitter34, which approximately reduces the optical power density to 1/280. The structure and optical microscope image of the SNG-based large-aperture emitter are shown in Fig. 4(a,b), respectively. (Detailed fabrication procedures are given in the methods.) We measured the time-domain curves from the large-aperture emitters, then replaced the receiver with a calibrated commercial pyro-electric detector (THz5I-BL-BNC, Gentec-EO) for absolute power measurements. The results obtained are illustrated in Fig. 5(a–c).

Bottom Line: Photoconductive antennas with nano-structured electrodes and which show significantly improved performances have been proposed to satisfy the demand for compact and efficient terahertz (THz) sources.Plasmonic field enhancement was previously considered the dominant mechanism accounting for the improvements in the underlying physics.Our findings will pave the way for new perspectives in the design and analysis of plasmonic nano-structures for more efficient THz photonic devices.

View Article: PubMed Central - PubMed

Affiliation: THz Photonics Creative Research Center, Future Research Creative Laboratory, Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-700, Korea.

ABSTRACT
Photoconductive antennas with nano-structured electrodes and which show significantly improved performances have been proposed to satisfy the demand for compact and efficient terahertz (THz) sources. Plasmonic field enhancement was previously considered the dominant mechanism accounting for the improvements in the underlying physics. However, we discovered that the role of plasmonic field enhancement is limited and near-field distribution of bias field should be considered as well. In this paper, we clearly show that the locally enhanced bias field due to the size effect is much more important than the plasmonic enhanced absorption in the nano-structured electrodes for the THz emitters. Consequently, an improved nano-electrode design is presented by tailoring bias field distribution and plasmonic enhancement. Our findings will pave the way for new perspectives in the design and analysis of plasmonic nano-structures for more efficient THz photonic devices.

No MeSH data available.


Related in: MedlinePlus