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Title: Tailored Fano resonance and localized electromagnetic field enhancement in Ag gratings

Abstract

Metallic gratings can support Fano resonances when illuminated with EM radiation, and their characteristic reflectivity versus incident angle lineshape can be greatly affected by the surrounding dielectric environment and the grating geometry. By using conformal oblique incidence thin film deposition onto an optical grating substrate, it is possible to increase the grating amplitude due to shadowing effects, thereby enabling tailoring of the damping processes and electromagnetic field couplings of the Fano resonances, hence optimizing the associated localized electric field intensity. To investigate these effects we compare the optical reflectivity under resonance excitation in samples prepared by oblique angle deposition (OAD) and under normal deposition (ND) onto the same patterned surfaces. We observe that by applying OAD method, the sample exhibits a deeper and narrower reflectivity dip at resonance than that obtained under ND. This can be explained in terms of a lower damping of Fano resonance on obliquely deposited sample and leads to a stronger localized electric field. This approach opens a fabrication path for applications where tailoring the electromagnetic field induced by Fano resonance can improve the figure of merit of specific device characteristics, e.g. quantum efficiency (QE) in grating-based metallic photocathodes.

Authors:
 [1];  [2];  [3];  [1];  [1]
  1. The College of William and Mary, Williamsburg, VA (United States). Department of Physics
  2. The College of William and Mary, Williamsburg, VA (United States). Department of Physics; Helmholtz Zentrum Dresden-Rossendorf, Institute for Radiation Physics, Dresden (Germany)
  3. The College of William and Mary, Williamsburg, VA (United States). Department of Physics; Univ. of Virginia, Charlottesville, VA (United States). Dept. of Mechanical & Aerospace Engineering
Publication Date:
Research Org.:
The College of William and Mary, Williamsburg, VA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1423780
Grant/Contract Number:
SC0008546
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 36 MATERIALS SCIENCE; Nanophotonics and plasmonics; Surfaces; interfaces and thin films

Citation Formats

Li, Zhaozhu, Klopf, J. Michael, Wang, Lei, Yang, Kaida, and Lukaszew, Rosa A.. Tailored Fano resonance and localized electromagnetic field enhancement in Ag gratings. United States: N. p., 2017. Web. doi:10.1038/srep44335.
Li, Zhaozhu, Klopf, J. Michael, Wang, Lei, Yang, Kaida, & Lukaszew, Rosa A.. Tailored Fano resonance and localized electromagnetic field enhancement in Ag gratings. United States. doi:10.1038/srep44335.
Li, Zhaozhu, Klopf, J. Michael, Wang, Lei, Yang, Kaida, and Lukaszew, Rosa A.. Tue . "Tailored Fano resonance and localized electromagnetic field enhancement in Ag gratings". United States. doi:10.1038/srep44335. https://www.osti.gov/servlets/purl/1423780.
@article{osti_1423780,
title = {Tailored Fano resonance and localized electromagnetic field enhancement in Ag gratings},
author = {Li, Zhaozhu and Klopf, J. Michael and Wang, Lei and Yang, Kaida and Lukaszew, Rosa A.},
abstractNote = {Metallic gratings can support Fano resonances when illuminated with EM radiation, and their characteristic reflectivity versus incident angle lineshape can be greatly affected by the surrounding dielectric environment and the grating geometry. By using conformal oblique incidence thin film deposition onto an optical grating substrate, it is possible to increase the grating amplitude due to shadowing effects, thereby enabling tailoring of the damping processes and electromagnetic field couplings of the Fano resonances, hence optimizing the associated localized electric field intensity. To investigate these effects we compare the optical reflectivity under resonance excitation in samples prepared by oblique angle deposition (OAD) and under normal deposition (ND) onto the same patterned surfaces. We observe that by applying OAD method, the sample exhibits a deeper and narrower reflectivity dip at resonance than that obtained under ND. This can be explained in terms of a lower damping of Fano resonance on obliquely deposited sample and leads to a stronger localized electric field. This approach opens a fabrication path for applications where tailoring the electromagnetic field induced by Fano resonance can improve the figure of merit of specific device characteristics, e.g. quantum efficiency (QE) in grating-based metallic photocathodes.},
doi = {10.1038/srep44335},
journal = {Scientific Reports},
number = ,
volume = 7,
place = {United States},
year = {Tue Mar 14 00:00:00 EDT 2017},
month = {Tue Mar 14 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
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