Two-Dimensional Optical Lattice Solitons in Photovoltaic-Photorefractive Crystals
GUO Jian-Bang1, LU Ke-Qing1,2**, NIU Ping-Juan2, YU Li-Yuan2, XING Hai-Ying2
1State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academic of Sciences, Xi'an 710119 2School of Electronics and Information Engineering, Tianjin Polytechnic University, Tianjin 300160
Abstract：We study two families of two-dimensional bright lattice solitons in photovoltaic-photorefractive crystals. It is shown that self-focusing and self-defocusing lattice solitons are possible only when their power level exceeds a critical threshold. It is found that self-focusing lattice solitons exist not only in the semi-infinite band gap, but also in the first band gap, whereas self-defocusing lattice solitons exist only in the first band gap. The structures of these lattice solitons are also analyzed. Our results indicate that a self-focusing lattice soliton in the semi-infinite band gap is more confined than in the first band gap so its tails in the first band gap occupy many lattice sites; when a self-defocusing lattice soliton is close to the second band, the self-defocusing lattice soliton is more confined so its tails occupy a few lattice sites.
2012, Vol. 29 
