[1] [1] Segev M, Crosignani B, Yariv A, et al. Spatial solitons in photorefractive media [J]. Phys. Rev. Lett., 1992, 68(7): 923-926.

[2] [2] Duree G C, Schultz J L, Salamo G J, et al. Observation of self-trapping of an optical beam due to the photorefractive effect [J]. Phys. Rev. Lett., 1993, 71(4): 533-536.

[3] [3] Segev M, Valley G C, Crosignani B, et al. Steady-state spatial screening solitons in photorefractive materials with external applied field [J]. Phys. Rev. Lett., 1994, 73(24): 3211-3214.

[4] [4] Shih M F, Segev M, Valley G C, et al. Observation of two-dimensional steady-state photorefractive screening solitons [J]. Electron. Lett., 1995, 31(10): 826-827.

[5] [5] Valley G C, Segev M, Crosighani B, et al. Dark and bright photovoltaic solitons [J]. Phys. Rev. A, 1994, 50(14): R4457-R4460.

[6] [6] Taya M, Bashaw M C, Fejer M M, et al. Observation of dark photovoltaic spatial solitons [J]. Phys. Rev. A, 1995, 52(4): 3095-3100.

[7] [7] Liu J S, Lu K Q. Screening-photovoltaic spatial solitons in biased photovoltaic photorefractive crystals and their self-deflection [J]. J. Opt. Soc. Am. B, 1999, 16(4): 550-555.

[8] [8] Fazio E, Renzi F, Rinaldi R, et al. Screening-photovoltaic bright solitons in lithium niobate and associated single-mode waveguides [J]. Appl. Phys. Lett., 2004, 85(12): 2193-2195.

[9] [9] Carvalho M I, Singh S R, Christodoulides D N. Self-deflection of steady-state bright spatial solitons in biased photorefractive crystals [J]. Opt. Commun., 1995, 120(5): 311-315 .

[11] [11] Castro-Camus E, Magana L F. Prediction of the physical response for the two-photon photorefractive effect [J]. Opt. Lett., 2003, 28(13): 1129-1131.

[12] [12] Hou C F, Pei Y B, Zhou Z X. Spatial solitons in two-photon photorefractive media [J]. Phys. Rev. A, 2005, 71(5): 053817.

[13] [13] Hou C F, Zhang Y, Jiang Y Y. Photovoltaic solitons in two-photon photorefractive materials under open-circuit conditions [J]. Opt. Commun., 2007, 273(2): 544-548.

[14] [14] Lu K Q, Zhao W, Yang Y L. One-dimensional incoherently coupled grey solitons in two-photon photorefractive media [J]. Appl. Phys. B, 2007, 87(3): 469-473.

[15] [15] Srivasrava S, Konar S. Two-component coupled photovoltaic soliton pair in two-photon photorefractive materials under open circuit conditions [J]. Optics and Laser Tech., 2009, 41: 419-423.

[16] [16] Zhang G Y, Liu J S. Screening-photovoltaic spatial solitons in biased two-photo photovoltaic photorefractive crystals [J]. J. Opt. Soc. Am. B, 2009, 26(1): 113-120.