[1] Ashkin A, Dziedzic J M, Bjorkholm J E and Chu S 1986
Opt. Lett. 11 288

[2] Crocker J C 1997 J. Chem. Phys. 106 2837

[3] Gutsche C, Keyser U F, Kegler K and Kremer F 2007
Phys. Rev. E 76 031403

[4] Sun Z W, Xu S H, Dai G L, Li Y M, Lou L R, Liu Q S and Zhu
R Z 2003 J. Chem. Phys. 119 2399

[5] Sun Z W, Xu S H, Liu J, Li Y M, Lou L R and Xie J C 2005
J. Chem. Phys. 122 184904

[6] Harada Y and Asakura T 1996 Opt. Commun. 124
529

[7] Davis T J 2007 Opt. Express 15 2702

[8] Chaumet P C, Rahmani A and Nieto-Vesperinas M 2002
Phys. Rev. Lett. 88 123601

[9] Manley S, Gillette J M, Patterson G H, Shroff H, Hess H F,
Betzig E and Lippincott-Schwartz J 2008 Nature Methods 5
155

[10] Jacobsen V, Stoller P, Brunner C, Vogel V and Sandoghdar
V 2006 Opt Express 14 405

[11] Schultz S, Smith D R, Mock J J and Schultz D A 2000
Proc. Natl. Acad. Sci. USA 97 996

[12] Prikulis J, Svedberg F, Kall M, Enger J, Ramser K, Goksor
M and Hanstorp D 2004 Nano Lett. 4 115

[13] Cang H, Wong C M, Xu C S, Rizvi A H and Yang H 2006
Appl. Phys. Lett. 88 223901

[14] Zhou J H, Qu L J, Yao K, Zhong M C and Li Y M 2008
Chin. Phys. Lett. 25 329

[15] F\"{allman E and Axner O 2003 Opt. Appl. 42
3915

[16] Yao X C, Li Z L, Guo H L, Cheng B Y and Zhang D Z 2001
Chin. Phys. Lett. 18 432

[17] Roichman Y, Waldron A, Gardel E and Grier D G 2006
Appl. Opt. 45 3425

[18] Reihani S N S, Charsooghi M A, Khalesifard H R and
Golestanian R 2006 Opt. Lett. 31 766

[19] Ke P C and Gu M 1998 J. Mod. Opt. 45 2159

[20] Reihani S N S and Oddershede L B 2007 Opt. Lett.
32 1998