Anti-reflection coating design for metallic terahertz meta-materials
- Stockholm Univ. (Sweden). Department of Physics; CIC nanoGUNE Research Centre, Guipuzcoa (Spain)
- Emory Univ., Atlanta, GA (United States)
- Stockholm Univ. (Sweden). Department of Physics
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- CIC nanoGUNE Research Centre, Guipuzcoa (Spain); KERBASQUE, Basque Foundation for Science (Spain)
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.
- Research Organization:
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); Swedish Research Council (SRC); European Research Council (ERC); European Union Programme; Spanish Ministry of Economy, Industry and Competitiveness; National Science Foundation (NSF); USDOE
- Grant/Contract Number:
- AC02-76SF00515; 600398s; 715452; 737093; MDM-2016-0618; DMR-1504449; ECCS-1509794; E0635001; 2015-SLAC-100238-Funding
- OSTI ID:
- 1418183
- Alternate ID(s):
- OSTI ID: 1426160
- Journal Information:
- Optics Express, Vol. 26, Issue 3; ISSN 1094-4087
- Publisher:
- Optical Society of America (OSA)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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