[1] [1] Pendry J B, Holden A J, Stewart W J. Phys. Rev. Lett., 1996, 76: 4773.

[2] [2] Pendry J B, Hoden A J, Robbins D J. Miccrowave Theory and Techniques IEEE, 1999, 47: 2075.

[3] [3] Kanda N, Konishi K, Kueata-Gonokami M. Opt. Express, 2007, 15(18): 11117.

[4] [4] Wang Lei, Jiang Suhua, Hu Haifeng. Opt. Lett., 2014, 39(2): 311.

[5] [5] Liu Xiaojun, Gu Jianqiang, Singh Ranjan, et al. Appl. Phys. Lett., 2012, 100: 131101.

[6] [6] Wen Qiye, Zhang Huaiwu, Xie Yunsong. Appl. Phys. Lett., 2009 95: 241111.

[7] [7] He Jun, Li Qingmei, Shen Jingling. Proc. SPIE, Infrared, Millimeter-wave, and Terahertz Technologies Ⅱ, 2012, 8562: 85620N-1.

[8] [8] HU Dan, Wang Xinke, Feng Shengfei. Adv. Opt. Materials, 2013, 1(2): 186.

[9] [9] LI Binbin, Yan Shengmei, Xiaong Wei. Chinese Optics Letters, 2012, 10: S13102.

[10] [10] Han N R, Chen Z C, Lim C S. Opt. Express, 2011, 19(8): 6990.

[11] [11] Yang Yuanmu, Huang Ran, Cong Longqing. Appl. Phys. Lett., 2011, 98: 121114.