有偏压光伏光折变晶体中明暗矢量孤子的演化

提出了有偏压光伏光折变晶体中存在着明暗矢量孤子,它起源于对外电场的非均匀空间屏蔽和光伏效应.当光伏效应为零时,这些明暗矢量孤子就转化为明暗矢量屏蔽孤子,其物理系统就转化为明暗矢量屏蔽孤子的物理系统;当外电场为零时,这些明暗矢量孤子预言了明暗矢量光伏孤子,其物理系统预言了明暗矢量光伏孤子的物理系统.应用光束传播的方法讨论了这些明暗矢量孤子的稳定性.结果表明,当σ> 0 和(β+α-δ) > 0 时,在(β+α-δ)小于某一值的区域内,这些明暗矢量孤子是稳定的;其中σ为控制两光束强度的参数,β为与外偏压有关的参数,α和β为与晶体的光伏系数有关的参数;当σ<0和(β+α-δ) <0时,在(β+α-δ)大于某一值的区域内,这些明暗矢量孤子也是稳定的.

Evolution of Bright-Dark Vector Spatial Solitons in Biased Photorefractive-Photovoltaic Crystals

The bright-dark vector spatial solitons are predicted in biased photorefractive-photovoltaic crystals, which result from both the bulk photovoltaic effect and the spatially nonuniform screening of the external bias field. When the bulk photorefractive effect can be neglected, the physical system of these bright-dark vector solitons changes into that of bright-dark vector screening solitons, and these bright-dark vector solitons change into bright-dark vector screening solitons. When the external field is absent, the physical system of these bright-dark vector solitons predicts that of bright-dark vector photovoltaic solitons, and these bright-dark vector solitons predict bright-dark vector photovoltaic solitons. The stability of these bright-dark vector solitons is discussed using a beam propagation method. When σ>0 and (β+α-δ)>0, where σ is the parameter controlling the intensities of the two optical beams, α and δ are the parameters related to the photovoltaic constant, and β is the parameter related to external electric field, these bright-dark vector solitons are stable in the regime of (β+α-δ) being less than a certain value. When σ<0 and (β+α-δ)<0, these bright-dark vector solitons are also stable in the regime of (β+α-δ) being greater than a certain value.