[2] Liu Jinsong, Lu Keqing Screening-photovoltaic spatial solitons in biased photovoltaic photorefractive crystals and their self-deflection. J. Opt. Soc. Am. (B), 1999, 16(3):550～555

[3] Shih M F, Seger M, Valley G C et al.. Observation of two-dimensional steady-state photorefractive screening solitons. Electron. Lett., 1995, 31(10):826～836

[4] Valley G C, Seger M, Crosignani B et al.. Dark and bright photovoltaic spatial solitons. Phys. Rev. (A), 1994, 50(6):R4457～R4460