Merging and separation of polarization singularities in complex lattices  

作　　者：Mengyao Wang Tian Shi Luhui Ning Peng Liu Liangsheng Li Ning Zheng 王梦瑶;石天;宁鲁慧;刘鹏;李粮生;郑宁

机构地区：[1]School of Physics,Beijing Institute of Technology,Beijing 100081,China [2]National Key Laboratory of Scattering and Radiation,Beijing 100854,China [3]Army Engineering University of PLA Shijiazhuang Campus,Shijiazhuang 050003,China [4]Beijing Key Laboratory of Optical Detection Technology for Oil and Gas,College of Science,China University of Petroleum-Beijing,Beijing 102249,China [5]Basic Research Center for Energy Interdisciplinary,College of Science,China University of Petroleum-Beijing,Beijing 102249,China

出　　处：《Chinese Physics B》2025年第3期512-519,共8页中国物理B(英文版)

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.12374205)。

摘　　要：The evolution in momentum space of bound states in the continuum(BICs)and circularly polarized states(CPSs)—as far-field polarization singularities—can be observed by controlling the geometric parameters of photonic crystals.This offers significant potential in optics and photonics.Here,we reveal that in complex lattices far-field polarization singularities can be flexibly manipulated while preserving structural symmetry.A change in topological charge for the at-ΓBIC can generate new BICs or CPSs.At an off-Γpoint,a BIC can spawn from the collision of two CPSs.As the thickness of the structure increases,this BIC will meet the at-ΓBIC.The merging of BICs can induce topological charge transition and yield a large wavevector space around theΓpoint with ultra-high quality(Q)factors.Our findings provide a novel degree of freedom for manipulating polarization singularities,which holds great promise in radiation modulation and singular optics.

关 键 词：bound states in the continuum circularly polarized states topological charge far-field polarization photonic crystals 

分 类 号：O17[理学—数学]