Waveguide arrays with spatially inhomogeneous nonlinearity

在这个研究项目中，我们将研究有效非线性分布不均匀或调制分布的一维光子晶格(波导阵)中的光波传播。虽然最近已经发表了大量的理论工作，其动机是与其他波系统如超冷量子气体的相似，但实际上到目前为止还没有对这个有吸引力的方向进行实验研究，这仅仅是因为缺少一个合适的实验模型系统。在光折变铌酸锂光波导阵列中，我们可以利用局部扩散处理来改变单通道空间尺度上的非线性大小。在这样的系统中，我们计划通过实验研究非线性波动现象，如不稳定性、Bloch振荡、Fano共振或不同类型孤子的存在，并对这些效应进行理论建模和模拟。

In this research project we will investigate optical wave propagation in one-dimensional photonic lattices (waveguide arrays) having an inhomogeneous or modulated distribution of the effective nonlinearity. Although a large number of theoretical works have been recently published, motivated by the close analogies to other wave systems like e.g. ultra-cold quantum gases, in fact no experimental investigation of this attractive direction has been performed so far, simply because a suitable experimental model system was missing. In photorefractive lithium niobate waveguide arrays we can use local diffusion treatment to modify the size of the nonlinearity on the spatial scale of single channels. In such systems we plan to investigate experimentally nonlinear wave phenomena like instabilities, Bloch oscillations, Fano resonances or the existence of different kinds of solitons, supported by theoretical modelling and simulations of these effects.