报告题目：Nonlinear phenomena in polariton topological insulators
科技处 前沿院 文理学院
Yaroslav Kartashov 教授是俄罗斯科学院光谱研究所理论系的首席科学家，同时也是巴塞罗那光子科学研究所(ICFO-The Institute of Photonics Sciences)的客座教授。年仅42岁，但已经在光学和物理学主流刊物上发表了260多篇，包括二十多篇Physics Review Letters, 并在物理系上顶尖期刊如Reviews of Modern Physics (IF 36.367), Progress in Physics (IF 14.257) 发表了多篇Review性质的文章。是非线性光学和拓扑光子学领域内非常著名的专家和具有重要影响力的学者，是Optics Letters期刊非线性光学方向的编辑，也是OSA主办的Nonlinear Photonics历年年会的总主席和众多具有国际重要影响力的会议的组织者。
Nonlinear phenomena in polariton topological insulators
In this presentation I will address unique system allowing investigation of the interplay between nonlinearity and topology - polariton condensates in optical microcavities. Optical microcavities supporting exciton-polariton quasi-particles offer one of the most powerful platforms for the investigation of rapidly developing area of topological photonics in general, and of photonic topological insulators in particular. Energy bands of polaritons in arrays of microcavity pillars arranged into various lattice configurations, such as honeycomb or Lieb, are readily controlled by the magnetic field and strongly influenced by the spin-orbit coupling effects, a combination leading to formation of unidirectional edge states in polariton topological insulators. In this presentation I will depart from the linear limit of non-interacting polaritons and address properties of nonlinear topological edge states, describe their instabilities resulting in the formation of localized topological quasi-solitons, which are exceptionally robust and immune to backscattering wavepackets propagating along the edge of the array of microcavity pillars. Both bright and dark topological quasi-solitons will be considered. I will also discuss bistability effects appearing in resonantly pumped polariton condensates in dissipative structured microcavities and describe how polarization and frequency of the pump beam may be used to control stability and localization of the excited nonlinear edge states that can be completely stable in such nonlinear "driven" systems. Finally, a variety of resonant phenomena with topological edge states that can be induced by temporal modulations of the underlying lattice of microcavity pillars will be discussed.