Electric field enhancement and far-field radiation pattern of the nanoantenna with concentric rings.

PAPER pubmed Nanoscale research letters 2014 Other Effect: benefit Evidence: Insufficient

Read original paper → DOI: 10.1186/1556-276x-9-681 PMID: 26088981 Evidence Lab

Abstract

The optical antennas have the potential in various applications because of their field enhancement and directivity control. The directivity of a dipole antenna can be improved by directivity-enhanced Raman scattering structure, which is a combination of a dipole antenna and a ring reflector layer on a ground plane. The concentric rings can collect the light into the center hole. Depending upon the geometry of the antenna inside the hole, different electric field enhancements can be achieved. In this paper, we propose to combine the concentric rings with the directivity-enhanced Raman scattering structure in order to study its electric field enhancement and the far-field radiation pattern by finite-difference time-domain simulations. Compared with the structure without the concentric rings over the ground plane, it is found that our proposed structure can obtain stronger electric field enhancements and narrower radiation beams because the gold rings can help to couple the light into the nanoantenna and they also scatter light into the far field and modify the far-field radiation pattern. The designed structures were fabricated and the chemical molecules of thiophenol were attached on the structures for surface-enhanced Raman scattering (SERS) measurements. The measured results show that the structure with concentric rings can have stronger SERS signals. The effects of the dielectric layer thickness in our proposed structure on the near-field enhancements and far-field radiation are also investigated. The proposed structure can be useful for several nanoantenna applications, such as sensing or detecting.

AI evidence extraction

At a glance

Study type

Other

Effect direction

benefit

Population

—

Sample size

—

Exposure

nanoantenna (optical antenna)

Evidence strength

Insufficient

Confidence: 74% · Peer-reviewed: yes

Main findings

Finite-difference time-domain simulations and SERS measurements indicate that adding concentric gold rings to a directivity-enhanced Raman scattering nanoantenna structure produces stronger electric field enhancements and narrower far-field radiation beams compared with a structure without concentric rings. Measurements with thiophenol attached to the fabricated structures showed stronger SERS signals for the structure with concentric rings. The influence of dielectric layer thickness on near-field enhancement and far-field radiation was also investigated.

Outcomes measured

electric field enhancement (near-field)
far-field radiation pattern / beam narrowing
surface-enhanced Raman scattering (SERS) signal strength
effect of dielectric layer thickness on near-field enhancement and far-field radiation

Limitations

Frequency/wavelength of operation not stated in the abstract
No quantitative effect sizes or statistical details reported in the abstract
Sample size and experimental replication details not provided in the abstract

View raw extracted JSON

{
    "study_type": "other",
    "exposure": {
        "band": null,
        "source": "nanoantenna (optical antenna)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "electric field enhancement (near-field)",
        "far-field radiation pattern / beam narrowing",
        "surface-enhanced Raman scattering (SERS) signal strength",
        "effect of dielectric layer thickness on near-field enhancement and far-field radiation"
    ],
    "main_findings": "Finite-difference time-domain simulations and SERS measurements indicate that adding concentric gold rings to a directivity-enhanced Raman scattering nanoantenna structure produces stronger electric field enhancements and narrower far-field radiation beams compared with a structure without concentric rings. Measurements with thiophenol attached to the fabricated structures showed stronger SERS signals for the structure with concentric rings. The influence of dielectric layer thickness on near-field enhancement and far-field radiation was also investigated.",
    "effect_direction": "benefit",
    "limitations": [
        "Frequency/wavelength of operation not stated in the abstract",
        "No quantitative effect sizes or statistical details reported in the abstract",
        "Sample size and experimental replication details not provided in the abstract"
    ],
    "evidence_strength": "insufficient",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "optical antenna",
        "nanoantenna",
        "concentric rings",
        "electric field enhancement",
        "far-field radiation pattern",
        "finite-difference time-domain (FDTD)",
        "surface-enhanced Raman scattering (SERS)",
        "thiophenol",
        "directivity"
    ],
    "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract/metadata and may be incomplete or incorrect. This content is for informational purposes only and is not medical advice.

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