[1] K. Watanabe, N. Horiguchi, and H. Kano, Appl. Opt. 46, 4985 (2007).
[2] W. Chen and Q. Zhan, Opt. Express 15, 4106 (2007).
[3] W. Chen and Q. Zhan, Chin. Opt. Lett. 5, 709 (2007).
[4] K. B. Rajesh and P. M. Anbarasam, Chin. Opt. Lett. 6, 785 (2008).
[5] S. Quabis, R. Dorn, M. Eberler, O. Gl¨ockl, and G. Leuchs, Opt. Commun. 179, 1 (2000).
[6] T. A. Nieminen, N. R. Heckenberg, and H. Rubinsztein-Dunlop, Opt. Lett. 33, 122 (2008).
[7] W.-C. Kim, N.-C. Park, Y.-J. Yoon, H. Choi, and Y.-P. Park, Opt. Rev. 14, 236 (2007).
[8] B. Richards and E. Wolf, Proc. Roy. Soc. A 253, 358 (1959).
[9] K. S. Youngworth and T. G. Brown, Opt. Express 7, 77 (2000).
[10] Y. Zhao, Q. Zhan, Y. Zhang, and Y.-P. Li, Opt. Lett. 30, 848 (2005).