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Radiation Engineering of Optical Antennas for Maximum Field Enhancement

Seok, Tae Joon and Jamshidi, Arash and Kim, Myungki and Dhuey, Scott and Lakhani, Amit and Choo, Hyuck and Schuck, Peter James and Cabrini, Stefano and Schwartzberg, Adam M. and Bokor, Jeffrey and Yablonovitch, Eli and Wu, Ming C. (2011) Radiation Engineering of Optical Antennas for Maximum Field Enhancement. Nano Letters, 11 (7). pp. 2606-2610. ISSN 1530-6984.

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Optical antennas have generated much interest in recent years due to their ability to focus optical energy beyond the diffraction limit, benefiting a broad range of applications such as sensitive photodetection, magnetic storage, and surfaceenhanced Raman spectroscopy. To achieve the maximum field enhancement for an optical antenna, parameters such as the antenna dimensions, loading conditions, and coupling efficiency have been previously studied. Here, we present a framework, based on coupled-mode theory, to achieve maximum field enhancement in optical antennas through optimization of optical antennas’ radiation characteristics. We demonstrate that the optimum condition is achieved when the radiation quality factor (Q_(rad)) of optical antennas is matched to their absorption quality factor (Q_(abs)). We achieve this condition experimentally by fabricating the optical antennas on a dielectric (SiO2) coated ground plane (metal substrate) and controlling the antenna radiation through optimizing the dielectric thickness. The dielectric thickness at which the matching condition occurs is approximately half of the quarter-wavelength thickness, typically used to achieve constructive interference, and leads to ∼20% higher field enhancement relative to a quarter-wavelength thick dielectric layer.

Item Type:Article
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URLURL TypeDescription Information
Choo, Hyuck0000-0002-8903-7939
Yablonovitch, Eli0000-0002-5724-3375
Additional Information:©2011 American Chemical Society. Received: February 3, 2011; Revised: May 11, 2011; Published: June 07, 2011. This work was supported in part by DARPA SERS S&T Fundamentals No. FA9550-08-1-0257. Work at the Molecular Foundry was supported by the Director, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The authors would like to thank Professor Luke P. Lee and Professor Kyoungsik Yu. The authors declare no competing financial interests.
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-08-1-0257
Department of Energy (DOE)DE-AC02-05CH11231
Defense Advanced Research Projects Agency (DARPA)UNSPECIFIED
Subject Keywords:Plasmonics, nano-optics, optical antenna, ground plane, impedance matching
Issue or Number:7
Record Number:CaltechAUTHORS:20150804-111047552
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Official Citation:Radiation Engineering of Optical Antennas for Maximum Field Enhancement Tae Joon Seok, Arash Jamshidi, Myungki Kim, Scott Dhuey, Amit Lakhani, Hyuck Choo, Peter James Schuck, Stefano Cabrini, Adam M. Schwartzberg, Jeffrey Bokor, Eli Yablonovitch, and Ming C. Wu Nano Letters 2011 11 (7), 2606-2610 DOI: 10.1021/nl2010862
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59178
Deposited By: Kristin Buxton
Deposited On:05 Aug 2015 22:51
Last Modified:09 Mar 2020 13:19

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