一维非厄密光子晶格中分叉可调无衍射光传输

理论计算和数值模拟了一维周期性复式光子晶格中光的分叉无衍射传输现象。当晶格满足退化的SSH模型时,波矢为±π的入射光将分裂为两束完全相同的对称无衍射光,且分叉夹角可通过耦合系数J来调节;在此基础上,通过微扰波导作用引入了调制相位φ,当微扰满足宇称时间对称时,只要入射光波矢k与调制相位φ之和为±π便能实现任意入射光波的无衍射分叉传输。进一步研究表明,次近邻耦合作用可以调控两个无衍射分叉光束的传输角度及其分功比。本研究为光学开关及未来全光路的设计提供了理论指导。

Bifurcation-tunable Diffractionless Light Propagation in Onedimensional Non-Hermitian Photonic Lattice

The light bifurcation transmission without diffraction in one-dimensional periodic compound photonic lattice was studied theoretically and numerically.When the lattice equals to degenerated SuSchrieffer-Heeger model,the incident light with the wave number k=±πwill bifurcate into two symmetric branches without any diffraction and the angles between two beams can be controlled by the coupling J between two lattice sites.In addition,a modulation phaseφis introduced.When the nonHermitian perturbations satisfy the parity-time symmetry,the diffractionless light bifurcation phenomenon with any incident light wave can be realized as long as the incident wave vector k and the modulation phaseφrespect the expression k+φ=±π.Further studies have shown that the next-nearest coupling can control the transmission angle and power division of two branches.This research provides new ideas for the design of optical switches and future all-optical paths.