We show that a flat metasurface with a parabolic reflection-phase distribution can focus an impinging plane wave to a point image in reflection geometry. Our system is much thinner than conventional geometric-optics devices and does not suffer the energy-loss issues encountered by many metamaterial devices working in transmission geometry. We designed realistic microwave samples and performed near-field scanning experiments to verify the focusing effect. Experimental results are in good agreement with full wave simulations, model calculations, and theoretical analyses.
© 2012 Optical Society of America
Original Manuscript: August 30, 2012
Revised Manuscript: October 29, 2012
Manuscript Accepted: November 5, 2012
Published: November 28, 2012
Xin Li, Shiyi Xiao, Bengeng Cai, Qiong He, Tie Jun Cui, and Lei Zhou, "Flat metasurfaces to focus electromagnetic waves in reflection geometry," Opt. Lett. 37, 4940-4942 (2012)