Small amplitude travelling wave solitons in biased photorefractive crystal

The positive and negative travelling wave solitons are predicted in photorefractive crystal biased by positive electric field in the low intensity regime. The amplitude and width of these solitons do not vary, showing the bright soliton properties, whereas the propagation properties of these solitons differ from previously observed steady-state photorefractive spatial solitons. These travelling wave solitons move on a straight line trajectory. The deflecting angle can be controlled by adjusting the parameter of the system.