扁长型微瓶腔中的回音壁模式选择及Fano谐振  

Selection of whispering-gallery modes and Fanoresonance of prolate microbottle resonators

作　　者：王梦宇 孟令俊[2] 杨煜 钟汇凯 吴涛 刘彬[1] 张磊[2] 伏燕军 王克逸[2] Wang Meng-Yu;Meng Ling-Jun;Yang Yu;Zhong Hui-Kai;Wu Tao;Liu Bin;Zhang Lei;Fu Yan-Jun;Wang Ke-Yi(Key Laboratory of Nondestructive Test,Ministry of Education,Nanchang Hangkong University,Nanchang 330063,China;Department of Precision Machinery and Precision Instrumentation,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]南昌航空大学,无损检测教育部重点实验室,南昌330063 [2]中国科学技术大学精密机械与精密仪器系,合肥230026

出　　处：《物理学报》2020年第23期108-117,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61775209,41871229,61275011);江西省重点研发计划(批准号:20192BBH80019)资助的课题.

摘　　要：微瓶腔在腔动力学、非线性光学、高灵敏度传感和微型激光器等领域具有非常大的应用潜力.首先,从亥姆霍兹方程出发,详细研究了微瓶腔中的模式场分布理论.利用电弧放电加工方法,制备了扁长型微瓶腔.其次,采用光纤锥波导耦合方式有效激发了微瓶腔中的径向模式和轴向模式,并且通过调节微瓶腔与波导的耦合间隙,实现了对微瓶腔的欠耦合、临界耦合和过耦合三种耦合状态控制.实验中,光谱中回音壁模式得到很好的模式定位和识别,最大品质因子Q值达到1.78×10^8.通过采用接触式耦合来增强调谐的稳定性,控制不同的耦合位置实现了谐振模式选择性激发,得到了稳定并且干净的谐振光谱.最后,通过选择光纤锥波导直径观察到了Fano谐振效应.所展示的结果对增强微腔传感、非线性光学和腔动力学等应用有重要意义.Optical microresonators supporting whispering-gallery modes have been intensively studied in past decades due to their practical applications ranging from fundamental science to engineering physics.Among such microresonators,microsphere resonators have been demonstrated to possess ultra-high quality(Q)factor,however,their shapes usually become non-standard spherical body,leading to irregular resonant spectra.Microring resonators have unique potential in integraibility on chip,but the fabrication imperfection limits their Q-factor only to 106.In addition,the free spectral range(FSR)just depends on their radius.Due to the advantages of high Q-factor,standard shape,slender mode field distribution,the microbottle resonators are demonstrated to possess excellent performance in cavity quantum dynamics,nonlinear optics,high-sensitivity sensing,and micro-laser.In this paper,we carry out a systematic study on the spectral characteristics of prolate microbottle resonator theoretically and experimentally.First,theoretically,the field distribution theory of the microbottle resonator is studied in detail based on Helmholtz equation.Experimentally,prolate microbottle resonators are fabriated via arc discharge technology.Second,the radial modes and axial modes of the microbottles are efficiently excited with the help of a coupled tapered fiber waveguide.By adjusting the coupling gap between the microbottle and the waveguide,The controlling of three cupling states i.e.undercoupling,critical coupling and overcoupling are realized.In our experiment,the whispering-gallery modes excited are identifiable and recognizable.The resonant mode with an ultra-high Q-factor of up to 1.78×10^8 is achieved.The characteristic of ultra-high Q-factor makes the microbottle hold great potential in biochemical sensing,nonlinear optics,and micro-laser.The tuning stability is enhanced by keeping the waveguide in touch with the microbottle.We investigate the selective excitation of whispering-gallery modes by adjusting different coupling points.As a r

关 键 词：光学微腔 微瓶腔 回音壁模式 模式选择 Fano 谐振 

分 类 号：TN25[电子电信—物理电子学]