光折变晶体中的光生伏打灰空间孤子

在自散焦介质中，平面波的传播对小的调制扰动是绝对稳定的，暗空间孤子正是作为平面波背景上的一种局域暗迹而存在的。基于这种调制稳定性，给出了由光生伏打自散焦非线性支持的一维灰空间孤子的演化方程，并在光生伏打光折变LiNbO3：Fe晶体中给出了它的静态解。数值研究了这种灰空间孤子的诸多性质：例如在不同的孤子灰度下的孤子轮廓和它的相位分布；光生伏打灰孤子的归一化横向传播速度和归一化半峰全宽随归一化的背景光强和孤子灰度的变化等。所有这些性质都可以通过调节孤子波两侧的相位差加以控制，并详细地比较了光生伏打灰孤子和屏蔽灰孤子之间的异同。

Photovoltaic Gray Spatial Solitons in Photorefractive Crystal

Plane waves are absolutely stable against small modulations in self-defocusing media, the dark spatial solitons exist only in the form localized dark hole on the plane wave background. Based on such modulation stability, the evolution equations for one-dimensional gray spatial solitons supported by the photovoltaic self-defocusing nonlinearity are presented and its stationary solution in photovoltaic photorefractive crystal LiNbO3∶Fe is given. The properties associated with these gray solitons are investigated numerically, such as soliton profile and its phase distribution for different values of soliton grayness, and the normalized transverse velocity and the normalized full width at half maximum (FWHM) of photovoltaic gray soliton as functions of normalized intensity and degree of grayness. These properties can be steered by adjusting the relative phase difference on either side of the soliton wave. Both similarities and differences between photovoltaic gray solitons and screening gray solitons are emphasized.