Towards large area THz electromagnetic metamaterials H.O. Moser* a , M. Bahou a , A. Chen a , S.P. Heussler a , L.K. Jian a , S.M.P. Kalaiselvi a , G. Liu a , S.M. Maniam a , Shahrain bin Mahmood a , P.D. Gu a , L. Wen a , J.A. Kong† b , H.S. Chen b , X.X. Cheng b , B.I. Wu b , B.D.F. Casse c , C. Rockstuhl, F. Lederer d , a Singapore Synchrotron Light Source (SSLS), National University of Singapore (NUS), 5 Research Link, Singapore 117603, Singapore; b Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; c Department of Physics and Electronic Materials Research Institute, Northeastern University, Boston, Massachusetts 02115, USA; d Institute of Solid-State Theory and Condensed Matter Optics, Friedrich Schiller University Jena, Max-Wien Platz 1, 07743 Jena, Germany ABSTRACT Up to date, electromagnetic metamaterials (EM 3 ) have been mostly fabricated by primary pattern generation via electron beam or laser writer. Such an approach is time-consuming and may have limitations of the area filled with structures. Especially, electron beam written structures are typically confined to areas of a few 100×100 m 2 . However, for meaningful technological applications, larger quantities of good quality materials are needed. Lithography, in particular X-ray deep lithography, is well suited to accomplish this task. Singapore Synchrotron Light Source (SSLS) has been applying its LIGA process that includes primary pattern generation via electron beam or laser writer, X-ray deep lithography and electroplating to the micro/nano-manufacturing of high-aspect ratio structures to produce a variety of EM 3 structures. Starting with Pendry’s split ring resonators, we have pursued structure designs suitable for planar lithography since 2002 covering a range of resonance frequencies from 1 to 216 THz. More recently, string-like structures have also been included. Latest progress made in the manufacturing and characterization of quasi 3D metamaterials having either split ring or string structures over areas of about 1 cm 2 extension will be described. Keywords: Metamaterials, Left-handed materials, Microstructure fabrication, infrared, Synchrotron radiation. 1. INTRODUCTION The very notion of a material implies a non-specific, copious, and cheap supply of the material that can be re-shaped to pieces according to the intended purpose. Although dubbed materials, metamaterials are not there yet. They still represent devices built for an intended function. Moreover, most of these devices were built using primary pattern generation (PPG), preferentially electron beam writing. Some examples are shown in Fig. 1. On the way towards metamaterials as real materials, there are the options of UV lithography and X-ray deep lithography to achieve larger scale batch production, and, eventually, plastic moulding, all in combination with electroplating or electroforming. The choice between UV and X-rays will depend on the depth of the structure elements and their aspect ratio. During the past years, SSLS has demonstrated the applicability of such processes to the fabrication of metamaterials. 2. MICRO/NANO EQUIPMENT AND PROCESS BASIS AT SSLS The schematic layout of the facilities at the Singapore Synchrotron Light Source (SSLS) is shown in Fig. 2. Besides LiMiNT and ISMI (acronyms spelled out in figure caption 2) that bear the lion’s share of the micro/nano-manufacturing and the spectroscopic characterization of EM 3 , the other beamline facilities also make occasional contributions to analytical issues of metamaterials. *moser@nus.edu.sg , http://ssls.nus.edu.sg , to whom correspondence should be addressed; † deceased; Invited Paper Metamaterials: Fundamentals and Applications, edited by Mikhail A. Noginov, Nikolay I. Zheludev, Allan D. Boardman, Nader Engheta, Proc. of SPIE Vol. 7029, 70290E, (2008) · 0277-786X/08/$18 · doi: 10.1117/12.794395 Proc. of SPIE Vol. 7029 70290E-1 2008 SPIE Digital Library -- Subscriber Archive Copy