Observation of miniaturized bound states in the continuum with ultra-high quality factors  

极高品质因子微缩化连续区束缚态观测

作　　者：Zihao Chen Xuefan Yin Jicheng Jin Zhao Zheng Zixuan Zhang Feifan Wang Li He Bo Zhen Chao Peng 陈子豪;尹雪帆;金纪诚;郑昭;张子璇;王非凡;何力;甄博;彭超(State Key Laboratory of Advanced Optical Communication Systems and Networks,Department of Electronics&Frontiers Science Center for Nano-optoelectronics,Peking University,Beijing 100871,China;Department of Physics and Astronomy,University of Pennsylvania,Philadelphia,PA 19104,USA;Peng Cheng Laboratory,Shenzhen 518055,China)

机构地区：[1]State Key Laboratory of Advanced Optical Communication Systems and Networks,Department of Electronics&Frontiers Science Center for Nano-optoelectronics,Peking University,Beijing 100871,China [2]Department of Physics and Astronomy,University of Pennsylvania,Philadelphia,PA 19104,USA [3]Peng Cheng Laboratory,Shenzhen 518055,China

出　　处：《Science Bulletin》2022年第4期359-366,M0003,共9页科学通报（英文版）

基　　金：partly supported by the National Natural Science Foundation of China(61922004 and 62135001);the National Key Research and Development Program of China(2020YFB1806405);the Major Key Project of PCL(PCL2021A14);the Open Fund of the State Key Laboratory of Integrated Optoelectronics;US National Science Foundation through the University of Pennsylvania Material Research Science and Engineering Center(DMR-1720530);US Office of Naval Research(ONR)Multidisciplinary University Research Initiative(MURI)Grant N00014-20-1-2325 on Robust Photonic Materials with High-Order Topological Protection;the US Army Research Office under award contract W911-NF-19-1-0087。

摘　　要：Light trapping is a constant pursuit in photonics because of its importance in science and technology.Many mechanisms have been explored,including the use of mirrors made of materials or structures that forbid outgoing waves,and bound states in the continuum that are mirror-less but based on topology.Here we report a compound method,combining lateral mirrors and bound states in the continuum in a cooperative way,to achieve a class of on-chip optical cavities that have high quality factors and small modal volumes.Specifically,light is trapped in the transverse direction by the photonic band gap of the lateral hetero-structure and confined in the vertical direction by the constellation of multiple bound states in the continuum.As a result,unlike most bound states in the continuum found in photonic crystal slabs that are de-localized Bloch modes,we achieve light-trapping in all three dimensions and experimentally demonstrate quality factors as high as Q=1.09×10^(6)and modal volumes as low as V=17.74(λ_(0)/n)^(3)in the telecommunication regime.We further prove the robustness of our method through the statistical study of multiple fabricated devices.Our work provides a new method of light trapping,which can find potential applications in photonic integration,nonlinear optics and quantum computing.光束缚在科学和技术上的重要价值使之成为了一个学界不断探索的研究领域.光束缚可利用材料或者结构反射镜实现,也可利用拓扑保护连续区束缚态构成的无反射镜结构实现.将面内反射边界与连续区束缚态结合,即可实现一类具有极高品质因子、极小模式体积的新型片上光学微腔.具体来说,利用光子晶体异质结构引入的光子禁带在水平方向将光约束在有限区域内,同时调控动量空间中连续区束缚态构成的拓扑星座实现垂直方向上的光约束,最终可实现全三维空间中的光束缚.本文在实验中观测到了高达1.09×10^(6)的品质因子,其模式体积仅为17.74(λ_(0)/n)^(3).多个样品表征结果的统计分析表明,该设计具有优秀的工艺鲁棒性.本研究为在微小尺度上实现光束缚提供了一种新的设计范式,在光子集成、非线性光学以及量子计算等领域具有可期的应用前景.

关 键 词：Bound state in the continuum Photonic crystal High-Q cavity Topological photonics 

分 类 号：O43[机械工程—光学工程]