Abstract-Terahertz focusing of multiple wavelengths by graphene metasurfaces

Liming Liu^1,2,a), Yair Zarate¹, Haroldo T. Hattori², Dragomir N. Neshev^1,3, Ilya V. Shadrivov¹ and David A. Powell^1,3
 HIDE AFFILIATIONS
1 Nonlinear Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia
2 School of Engineering and Information Technology, University of New South Wales, Canberra, ACT 2612, Australia
3 Centre for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS), Australian National University, Canberra, ACT 2601, Australia
a) Author to whom correspondence should be addressed. Electronic mail:liming.liu@student.adfa.edu.au
Appl. Phys. Lett. 108, 031106 (2016); http://dx.doi.org/10.1063/1.4940231

http://scitation.aip.org/content/aip/journal/apl/108/3/10.1063/1.4940231?TRACK=RSS

Metasurfaces can achieve nearly arbitrary wavefront control based on manipulation of the wavephase profile. We propose a metasurface based on double graphene cut-wire resonatorswhich can cover the complete 2π phase region with high reflection efficiency. This full phase coverage is essential for efficient wavefront manipulation, without reflecting energy into unwanted channels. A mirror capable of focusing multiple wavelengths is demonstrated numerically based on the proposed structure. The mirror can effectively focus terahertz (THz)waves from 1.2 to 1.9 THz to the same focal point by changing the Fermi level of eachgrapheneresonator separately. The presented metasurface could provide a powerful platform for controlling THz waves, including focusing, beam steering, beam shaping, and holograph