[1] S. N. Khonina, V. V. Kotlyar, R. V. Skidanov, V. A.Soifer, K. Jefimovs, J. Simonen, and J. Turunen, J. Mod. Opt. 51, 2167 (2004).

[2] C. Xie, X. Zhu, and J. Jia, Opt. Lett. 34, 3038 (2009).

[3] C. Xie, X. Zhu, L. Shi, and M. Liu, Opt. Lett. 35, 1765 (2010).

[4] S. Franke-Arnold, J. Leach, M. Padgett, V. Lembessis, D. Ellinas, A. Wright, J. Girkin, P. Ohberg, and A. Arnold, Opt. Express 15, 8619 (2007).

[5] A. Bekshaev and M. Soskin, Opt. Lett. 31, 2199 (2006).

[6] P. Vaity and R. P. Singh, Opt. Lett. 36, 2994 (2011).

[7] L. Sacconi, E. Froner, R. Antolini, M. R. Taghizadeh, A. Choudhury, and F. S. Pavone, Opt. Lett. 28, 1918 (2003).

[8] W. M. Lee, X.-C. Yuan, and D. Y. Tang, Opt. Express 11, 199 (2003).

[9] L. Paterson, M. P. MacDonald, J. Arlt, W. Sibbett, P. E. Bryant, and K. Dholakia, Science 292, 912 (2001).

[10] B. P. S. Ahluwalia, X.-C. Yuan, K. J. Moh, and J. Bu, Appl. Phys. Lett. 91, 171102 (2004).

[11] V. V. Kotlyar, V. A. Soifer, and S. N. Khonina, J. Mod. Opt. 44, 1409 (1997).

[12] P. Paakkonen, J. Lautanen, M. Honkanen, M. Kuittinen, J. Turunen, S. N. Khonina, V. V. Kotlyar, V. A. Soifer, and A. T. Friberg, J. Mod. Opt. 45, 2355 (1998).

[13] V. V. Kotlyar, S. N. Khonina, R. V. Skidanov, and V. A. Soifer, Opt. Commun. 274, 8 (2007).

[14] X. Sun, C. Zhou, H. Ru, Y. Zhang, and B. Yu, Chin. Opt. Lett. 2, 4 (2004).

[15] A. Cheng, J. T. Goncalves, P. Golshani, K. Arisaka, and C. Portera-Cailliau, Nat. Meth. 8, 139 (2011).

[16] K. Obata, J. Koch, U. Hinze, and B. N. Chichkov, Opt. Express 18, 17193 (2010).

[17] J. Bewersdorf, R. Pick, and S. W. Hell, Opt. Lett. 23, 655 (1998).

[18] N. R. Heckenberg, R. McDuff, C. P. Smith, and A. G. White, Opt. Lett. 17, 221 (1992).

[19] D. Cojoc, B. Kaulich, A. Carpentiero, S. Cabrini, L. Businaro, and E. Di Fabrizio, Microelectron. Eng. 83, 1360 (2006).

[20] A. Sakdinawat and Y. Liu, Opt. Lett. 32, 2635 (2007).