光子学报, 2018, 47 (3): 0324003, 网络出版: 2018-02-01
金属和自散焦周期性介质界面表面间隙孤子的研究
Surface Gap Solitons at the Interface between a Metal and a Self-defocusing Periodic Medium
光折变晶体 非线性光学 表面光学 间隙孤子 光格子 Photorefractive crystal Nonlinear optics Optics at surface Gap solitons Photonic lattices
摘要
研究了金属和自散焦周期性介质界面表面间隙孤子的形成及其稳定性.这种表面间隙孤子只存在于超过格子深度临界值的有限间隙内, 在第一间隙和第二间隙内间隙孤子存在区域包括稳定区域和不稳定区域, 第二间隙内格子深度的临界值远大于第一间隙内格子深度的临界值.在第一间隙内, 对给定的格子深度, 当传播常数增大时, 表面间隙孤子的能流变小, 格子区域内表面间隙孤子振荡拖尾变短.对给定的传播常数, 表面间隙孤子的能流随格子深度的增加而增大, 增大格子深度能把表面间隙孤子由不稳定态转为稳定态.不稳定表面间隙孤子在传输中向横轴正向偏转, 偏转角度随格子深度的增加而变小, 其主瓣传播轨迹是一条锯齿形曲线.在第二间隙内, 表面间隙孤子有较多的拖尾振荡, 不稳定区域靠近存在区域的上限, 并且随着传播常数增加而逐渐减小.
Abstract
The formation and stability of surface gap solitons at the interface between a metal and a self-defocusing periodic media are investigated. Such type of surface gap solitons exist only in finite gaps when the lattice depth exceeds a critical value. In the first and second gap, the existence domain of surface gap solitons includes both stable and unstable domains. The critical value of the lattice depth in the second gap is much larger than the critical value of the lattice depth in the first gap. In the first finite gap, if the lattice depth is fixed, the energy flow of surface gap solitons decreases with an increase of the propagation constant, surface gap solitons have short oscillating tails in the lattice region when the propagation constant is increased. For a given propagation constant, the energy flow of surface gap solitons increases with lattice depth increasing, and surface gap solitons can be switched from unstable state to stable state by changing the lattice depth. Unstable surface gap solitons tend to self-bend toward the positive direction of the transverse axis during propagation. The self-deflection angle decreases with an increase of the lattice depth. The trajectory of the main lobe of surface gap soliton is a zigzag curve. In the second gap, surface gap solitons have more tail oscillations, and the unstable domain is close to the upper bound of the existing domain. With the propagation constant increasing, the unstable domain decreases gradually.
赵冲, 卢克清, 高立许, 陈卫军, 惠娟利. 金属和自散焦周期性介质界面表面间隙孤子的研究[J]. 光子学报, 2018, 47(3): 0324003. ZHAO Chong, LU Ke-qing, GAO Li-xu, CHEN Wei-jun, HUI Juan-li. Surface Gap Solitons at the Interface between a Metal and a Self-defocusing Periodic Medium[J]. ACTA PHOTONICA SINICA, 2018, 47(3): 0324003.