[1] R. A. Shelby, D. R. Smith, and S. Schultz, Science 292, 77 (2001).
[2] Z. Liu, H. Lee, Y. Xiong, C. Sun, and X. Zhang, Science 315, 1686 (2007).
[3] K. Kawase, Y. Ogawa, Y. Watanabe, and H. Inoue, Opt. Express 11, 2549 (2003).
[4] I. I. Smolyaninov, Y.-J. Hung, and C. C. Davis, Science 315, 1699 (2007).
[5] J. B. Pendry, D. Schurig, and D. R. Smith, 312, 1780 (2006).
[6] D. Schurig, J. J. Mock, B. J. Justice, S. A. Cummer, J. B. Pendry, A. F. Starr, and D. R. Smith, Science 314, 977 (2006).
[7] S. Zhang, Y.-S Park, J. Li, X. Lu, W. Zhang, and X. Zhang, Phys. Rev. Lett. 102, 023901-1 (2009).
[8] J. K. Gasnsel, M. Thiel, M. S. Rill, M. Decker, K. Bade, V. Saile, G. von Freymann, S. Linden, and M. Wegener, Science 325, 1513 (2009).
[9] E. Plum, J. Zhou, J. Dong, V. A. Fedotov, T. Koschny, C. M. Soukoulis, and N. I. Zheludv, Phys. Rev. B 79, 035407-1 (2009).
[10] M. Decker, M. W. Klein, M. Wegener, and S. Linden, Opt. Lett. 32, 856 (2007).
[11] A. Demetriadou and J. B. Pendry, J. Phys.: Condens. Matter 21, 376003 (2009).
[12] T. G. Mackay and A. Lakhtakia, SPIE Reviews 1, 018003-1 (2010).
[13] B. Wang, J. Zhou, T. Koschny, M. Kafesaki, and C. M. Soukoulis, J. Opt. A: Pure Appl. Opt. 11, 114003 (2009).
[14] J. Gu, J. Han, X. Lu, R. Singh, Z. Tian, Q. Xing, and W. Zhang, Opt. Express 17, 20307 (2009).
[16] Y. Wang, Z. Zhao, Z. Chen, L. Zhang, and K. Kang, Chin. Opt. Lett. 7, 690 (2009).