Nonlinear topological valley Hall edge states arising from type-II Dirac cones

来源 :AdvancedPhotonics | 被引量 : 0次 | 上传用户:carboy123
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
A Dirac point is a linear band crossing point originally used to describe unusual transport properties of materials like graphene. In recent years, there has been a surge of exploration of type-II Dirac/Weyl points using various engineered platforms including photonic crystals, waveguide arrays, metasurfaces, magnetized plasma and polariton micropillars, aiming toward relativistic quantum emulation and understanding of exotic topological phenomena. Such endeavors, however, have focused mainly on linear topological states in real or synthetic Dirac/Weyl materials. We propose and demonstrate nonlinear valley Hall edge (VHE) states in laser-written anisotropic photonic lattices hosting innately the type-II Dirac points. These self-trapped VHE states, manifested as topological gap quasi-solitons that can move along a domain wall unidirectionally without changing their profiles, are independent of external magnetic fields or complex longitudinal modulations, and thus are superior in comparison with previously reported topological edge solitons. Our finding may provide a route for understanding nonlinear phenomena in systems with type-II Dirac points that violate the Lorentz invariance and may bring about possibilities for subsequent technological development in light field manipulation and photonic devices.
其他文献
本文设计了一种新型的偏振棱镜系统,它具有损耗小、隔离度高、结构紧凑、调试方便等诸多优点。该偏振棱镜系统的损耗为0.6 dB,隔离度为24 dB。以此为基础做成的光纤环形器指标为,波长在1.3 μm时,插入损耗(包括光纤对接损耗):2.2~2.4 dB,隔离度:20.5~23.1 dB。
提出了一种基于底部反射增强的GaAs纳米线径向p-i-n结阵列的太阳能电池,利用有限差分时域法和有限元方法对其光谱吸收和光伏性能进行了研究。结果表明,将聚合物和衬底之间的SiO2替换为低折射率的MgF2介质层,不仅显著降低了衬底的吸收损耗,还显著提高了纳米线阵列在整个波长范围内对光的吸收率。此外,通过优化i区厚度和纳米线长度,可将太阳能电池的光电转换效率提升至13.9%。该研究为实现低成本、高性能的纳米太阳能电池提供了一条可行途径。
用KTP晶体研制成LD泵浦的YAG腔内倍频激光器,得到0.532 μm连续绿色线偏振激光输出,阈值泵浦功率为41 mW,输出功率为1.4 mW,斜效率为1.7%。研究了泵浦光对倍频激光横模的影响。
A dual-wavelength fiber laser operating at the 1550 nm region using a side-polished arc-shaped fiber with deposited ZnO nanoparticles is proposed and demonstrated. The arc-polished fiber is fabricated by using a simple but novel approach in which a silico
期刊
提出了相移全息CT技术。实验中采用双参考光相移方法在再现阶段引入相移,重建了双烛火焰层面的温度场,结果表明,这一技术能够快速、高精度地获取各个投影响方向上的位相分布,重建出令人满意的结果。
设计并制备了基于人工超表面/离子凝胶/石墨烯复合结构的太赫兹调幅器件,并对其调制效果进行了模拟仿真和实验验证。该器件以嵌在石墨烯和超表面之间的离子凝胶为电解质,以石墨烯为主动材料,用超表面实现太赫兹波与石墨烯相互作用的增强。通过外加偏压调节石墨烯的电导率,进而达到对太赫兹波的主动控制。结果表明:该器件在较小的外加偏压下就可以在谐振频率处实现73%的调制深度,并且在调制过程中谐振频率几乎保持不变。该器件为小电压下的大幅度太赫兹调制提供了一种新手段。
研制了一种具有高透射比和高抗光损伤能力的新型偏光器件.
期刊