Based on the one-dimensional periodic and Fibonacci-like waveguide arrays, we experimentally investigate localized quantum walks (QWs), both in the linear and nonlinear regimes. Unlike the ballistic transport behavior in conventional random QWs, localization of QWs is obtained in the Fibonacci-like waveguide arrays both theoretically and experimentally. Moreover, we verify the enhancement of the localization through nonlinearity-induced effect. Our work provides a valid way to study localization enhancement in QWs, which might broaden the understanding of nonlinearity-induced behaviors in quasi-periodic systems.

飞秒激光直写玻璃波导是快速制备三维集成光子芯片的一种重要手段，波导有效折射率的准确测量对于设计光子器件意义重大。设计并制备了一种断臂马赫-曾德尔干涉仪（MZI）结构对玻璃波导有效折射率进行原位精密测量。激光在断线区域和波导内的有效折射率不同，在传输相同长度下产生一定的相位差，最终导致不同的干涉结果。对断臂MZI结构的相位干涉结果进行处理，得到激光直写玻璃波导的有效折射率为1.504+7.7×10⁻⁴。利用RSOFT软件光束传播算法对器件进行模拟仿真，仿真结果与实验吻合良好。该精确测量玻璃波导有效折射率的方法对于提升光子芯片设计与制造能力具有重要意义。

改变激光脉宽，在硼铝硅酸盐玻璃内直写光波导，研究了脉冲宽度对光波导截面形貌、模场大小及定向耦合器透射比的影响。实验中，采用脉宽为239 fs单模/多模临界功率的激光制备光波导，其截面大小由5.4 μm×4.2 μm（239 fs）变为5.1 μm×2.4 μm（700 fs）；模场大小由6.2 μm×6 μm（239 fs）变为5.8 μm×4.8 μm（700 fs）且传输模式均为单模，模场形状逐渐从圆形变成椭圆形；定向耦合器的透射比在水平偏振下由97.8%（239 fs）变化为70.2%（700 fs），在垂直偏振下由99.2%（239 fs）变化为79.7%（700 fs）。实验发现脉宽在600 fs以上的激光不利于制备性能稳定的玻璃波导。

A 400 nm femtosecond laser was used to ablate the surface of a high-pressure and high-temperature diamond, and subwavelength surface micro structures with a period of 100 nm were achieved. A variety of micro-nano composite surface structures were prepared by changing the polarization direction and laser scanning direction. By dynamically adjusting the laser polarization and the laser scanning tracks, a maskless direct writing fabrication of micro-nano complex structures was realized. The micro-nano patterning on an ultra-hard and super-stabile diamond provides a new idea for the preparation of friction reducing surfaces, nano imprint transfer templates, surface enhanced Raman scattering test substrates, and micro-nano optical structures.