有偏压的光伏光折变晶体中低振幅的空间孤子

获得了有偏压的光伏光折变晶体中空间孤子传播的非线性波动方程 .它是屏蔽孤子和短路光伏孤子的非线性波动方程的统一形式 .在低振幅区域 ,由它得到了起源于对外电场的非均匀空间屏蔽和光伏效应的空间孤子 .在适当的条件下 ,这类孤子可以转化为屏蔽孤子和短路光伏孤子 .当外电场为某一值时 ,用改变外电场的极性和旋转光的偏振方向可以实现这类孤子的明暗转换

Low-Amplitude Spatial Solitons in Photovoltaic Photorefractive Crystals with External Bias Field

A theory of spatial solitions is developed for closed circuit photorefactive photovoltaic crystals. Spatial solitons result from both the photovoltaic effect and the spatially nonuniform screening of the external bias field. The properties of these solitions differ form those observed previously for steady state photorefractive spatial solitons. The nonlinear wave equation is derived; it describes the stationary (solition) propagation of wave in photovoltaic crystals with external applied field. When the external bias field is much stronger such that the photovoltaic effect can be neglected, the nonlinear wave equation is similar to that for screening solitons. If the external bias field is absent, the nonlinear wave equation is similar to that for photovoltaic solitons in a closed or open circuit. In the low amplitude regime, an approximate analytic solution is obtained for the nonlinear wave equation. Under the appropriate conditions, these solitons change into screening and photovoltaic solitons. When external electric field is of a certain value, these solitons may be switched from bright to dark by changing the polarity of the external electric field and by rotating the polarization of the light.