光子晶格中光束演化的二能级模型及非线性Landau-Zener隧穿

推导了光束在Kerr介质、屏蔽介质及光伏介质的一维光子晶格中演化的二能级形式，给出了光束在这三种光折变介质中传播时二能级系统的经典哈密顿形式.以屏蔽介质为例，做出了空间相图，当非线性参数变化时，空间相图的拓扑改变.给出了空间相图的拓扑发生改变时，非线性参数的临界值.数值研究了非线性Landau-Zener（LZ）隧穿，得到非线性参数与LZ隧穿率的关系，发现非线性参数大于0时增强了隧穿，而非线性参数小于0时抑制了隧穿. 关键词： 二能级模型 光折变介质 光子晶格 非线性Landau-Zener隧穿

Two-level model of light propagation in photonic lattices and nonlinear Landau-Zener tunneling

We deduce a two-level model of light propagating in photonic lattices of Kerr medium and two kinds of saturated photorefractive medium,establish the classical Hamiltonian system, study the evolution of the phase-space motion of the Hamiltonian system for one kind of saturated photorefractive medium, namely, the Screening medium, and then study the nonlinear Landau-Zener tunneling numerically. Results show that the tunneling probability is enhanced when the nonlinearity is positive while it is restrained when the nonlinearity is negative.