Abstract-Free-standing terahertz chiral meta-foils exhibiting strong optical activity and negative refractive index

Jianfeng Wu¹, Binghao Ng², Shuvan P. Turaga¹, Mark B. H. Breese^1,3, Stefan A. Maier², Minghui Hong⁴, Andrew A. Bettiol¹, and Herbert O. Moser^5
1Department of Physics, Center for Ion Beam Applications (CIBA), National University of Singapore, 2 Science Drive, Singapore 
²Department of Physics, Imperial College, London SW7 2AZ, United Kingdom 
³Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, 117603 Singapore 
⁴Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117576 Singapore 
⁵Karlsruhe Institute of Technology (KIT), Network of Excellent Retired Scientists (NES), and Institute of Microstructure Technology (IMT), Postfach 3640, 76021 Karlsruhe, Germany 

http://apl.aip.org/resource/1/applab/v103/i14/p141106_s1?isAuthorized=no

A chiral meta-foil consisting of a self-supported square array of interconnected conjugated rosettes is demonstrated at terahertz frequencies. It exhibits strong optical activity and circular dichroism. Negative refractive index with a figure-of-merit as high as 4.2 is achieved, attributed to its free-standing nature. Experimental results are in good agreement with numerical simulation. Free-standing chiral meta-foils provide a unique approach to create a completely all-metal chiral metamaterial, which can be flexibly integrated into optical setups while eliminating dielectric insertion losses.

© 2013 AIP Publishing LLC

Abstract-Propagation of electromagnetic fields in bulk terahertz metamaterials: Combined experimental and theoretical study

http://prb.aps.org/accepted/fa077OecL541151c883286b1117d2dbf8361aec5a

Rasoul Alaee, Christoph Menzel, Agnieszka Banas, Krzysztof Banas, Su Xu, Hongsheng Chen, Herbert O. Moser, Falk Lederer, and Carsten Rockstuhl

Accepted Monday Jan 28, 2013

The availability of novel technologies that enable the fabrication of bulk metamaterials made it necessary to develop a theoretical language to discuss their properties appropriately. Here, we use, for the first time, the fundamental Bloch mode approximation to explore bulk properties of metamaterials that operate at terahertz frequencies. We demonstrate that this approximation is valid in the case of THz meta-foil metamaterials. While relying on theoretical and experimental results, we show that the fundamental Bloch mode approximation can explain minuscule details that are unique to the bulk metamaterial. Various applications such as cylindrical lenses, terahertz cloaks and sensors will benefit from our analysis.