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Title: Anti-reflection coating design for metallic terahertz meta-materials

Abstract

We demonstrate a silicon-based, single-layer anti-reflection coating that suppresses the reflectivity of metals at near-infrared frequencies, enabling optical probing of nano-scale structures embedded in highly reflective surroundings. Our design does not affect the interaction of terahertz radiation with metallic structures that can be used to achieve terahertz near-field enhancement. We have verified the functionality of the design by calculating and measuring the reflectivity of both infrared and terahertz radiation from a silicon/gold double layer as a function of the silicon thickness. We have also fabricated the unit cell of a terahertz meta-material, a dipole antenna comprising two 20-nm thick extended gold plates separated by a 2 μm gap, where the terahertz field is locally enhanced. We used the time-domain finite element method to demonstrate that such near-field enhancement is preserved in the presence of the anti-reflection coating. Finally, we performed magneto-optical Kerr effect measurements on a single 3-nm thick, 1-μm wide magnetic wire placed in the gap of such a dipole antenna. The wire only occupies 2% of the area probed by the laser beam, but its magneto-optical response can be clearly detected. Our design paves the way for ultrafast time-resolved studies, using table-top femtosecond near-infrared lasers, of dynamics inmore » nano-structures driven by strong terahertz radiation.« less

Authors:
 [1];  [2];  [3];  [4];  [2];  [5]; ORCiD logo [3]
  1. Stockholm Univ. (Sweden). Department of Physics; CIC nanoGUNE Research Centre, Guipuzcoa (Spain)
  2. Emory Univ., Atlanta, GA (United States)
  3. Stockholm Univ. (Sweden). Department of Physics
  4. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  5. CIC nanoGUNE Research Centre, Guipuzcoa (Spain); KERBASQUE, Basque Foundation for Science (Spain)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Swedish Research Council (SRC); European Research Council (ERC); European Union Programme; Spanish Ministry of Economy, Industry and Competitiveness; National Science Foundation (NSF)
OSTI Identifier:
1426160
Grant/Contract Number:  
AC02-76SF00515; 600398s; 715452; 737093; MDM-2016-0618; DMR-1504449; ECCS-1509794; E0635001
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Optics Express
Additional Journal Information:
Journal Volume: 26; Journal Issue: 3; Journal ID: ISSN 1094-4087
Publisher:
Optical Society of America (OSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Spectroscopy, terahertz; Femtosecond phenomena; Metamaterials; Magneto-optical materials

Citation Formats

Pancaldi, Matteo, Freeman, Ryan, Hudl, Matthias, Hoffmann, Matthias C., Urazhdin, Sergei, Vavassori, Paolo, and Bonetti, Stefano. Anti-reflection coating design for metallic terahertz meta-materials. United States: N. p., 2018. Web. doi:10.1364/oe.26.002917.
Pancaldi, Matteo, Freeman, Ryan, Hudl, Matthias, Hoffmann, Matthias C., Urazhdin, Sergei, Vavassori, Paolo, & Bonetti, Stefano. Anti-reflection coating design for metallic terahertz meta-materials. United States. doi:10.1364/oe.26.002917.
Pancaldi, Matteo, Freeman, Ryan, Hudl, Matthias, Hoffmann, Matthias C., Urazhdin, Sergei, Vavassori, Paolo, and Bonetti, Stefano. Fri . "Anti-reflection coating design for metallic terahertz meta-materials". United States. doi:10.1364/oe.26.002917. https://www.osti.gov/servlets/purl/1426160.
@article{osti_1426160,
title = {Anti-reflection coating design for metallic terahertz meta-materials},
author = {Pancaldi, Matteo and Freeman, Ryan and Hudl, Matthias and Hoffmann, Matthias C. and Urazhdin, Sergei and Vavassori, Paolo and Bonetti, Stefano},
abstractNote = {We demonstrate a silicon-based, single-layer anti-reflection coating that suppresses the reflectivity of metals at near-infrared frequencies, enabling optical probing of nano-scale structures embedded in highly reflective surroundings. Our design does not affect the interaction of terahertz radiation with metallic structures that can be used to achieve terahertz near-field enhancement. We have verified the functionality of the design by calculating and measuring the reflectivity of both infrared and terahertz radiation from a silicon/gold double layer as a function of the silicon thickness. We have also fabricated the unit cell of a terahertz meta-material, a dipole antenna comprising two 20-nm thick extended gold plates separated by a 2 μm gap, where the terahertz field is locally enhanced. We used the time-domain finite element method to demonstrate that such near-field enhancement is preserved in the presence of the anti-reflection coating. Finally, we performed magneto-optical Kerr effect measurements on a single 3-nm thick, 1-μm wide magnetic wire placed in the gap of such a dipole antenna. The wire only occupies 2% of the area probed by the laser beam, but its magneto-optical response can be clearly detected. Our design paves the way for ultrafast time-resolved studies, using table-top femtosecond near-infrared lasers, of dynamics in nano-structures driven by strong terahertz radiation.},
doi = {10.1364/oe.26.002917},
journal = {Optics Express},
number = 3,
volume = 26,
place = {United States},
year = {Fri Jan 26 00:00:00 EST 2018},
month = {Fri Jan 26 00:00:00 EST 2018}
}

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