基于法布里-珀罗腔的可调谐连续域束缚态及应用  

Tunable continuous domain bound states based on Fabry-Perot cavities and their applications

作　　者：任洋 李振雄 张磊 崔巍[1] 吴雄雄 霍亚杉 何智慧 Ren Yang;Li Zhen-Xiong;Zhang Lei;Cui Wei;Wu Xiong-Xiong;Huo Ya-Shan;He Zhi-Hui(Center for Optoelectronic Information and Transform,School of Physics and Electronic Information,Yan’an University,Yan’an 716000,China)

机构地区：[1]延安大学物理与电子信息学院,光电信息与转换中心,延安716000

出　　处：《物理学报》2024年第17期194-204,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62065017,12004327,52303352);陕西省重点研发计划(批准号:2024GX-YBXM-097);延安大学博士创业基金(批准号:YAU202313801);中国博士后科学基金(批准号:2020M680317);陕西省自然科学基金(批准号:2021JM-414)资助的课题.

摘　　要：优异的光学吸收器一直具备着高品质因数和完美吸收的特性,然而,这类吸收器通常会受到传统表面等离子体共振带来的欧姆损耗,制约其在实际应用中的吸收性能.本文提出了一种基于法布里-珀罗腔的可调谐连续域束缚态(bound state in the continuum,BIC),通过调整模型的参数,可将BIC可以转变为准BIC,在连续谱中实现了100%的完美吸收.在本文中,采用干涉理论探究了影响完美吸收的因素,用耦合模理论和阻抗匹配理论对准BIC进行理论计算,采用电场和磁场理论解释了吸收器完美吸收的物理机制.与传统吸收器相比,该吸收器具有优异的结构参数鲁棒性和广泛的BIC调控范围.更重要的是,该吸收器具有出色的传感性能,其最大灵敏度可达34 nm/RIU,最大品质因数为9.5.最后,该吸收器还实现了双频的开光性能,其中双频开关的最大调制深度和最小插入损耗分别为99.4%和0.0004 dB.这些研究结果在光子学、光通信、传感器技术等领域具有重要意义.Excellent optical absorbers are always characterized by high quality factors and perfect absorption;however,these absorbers usually encounter the ohmic losses due to traditional surface plasmon resonance,which limits their absorption performance in practical applications.To address the problem,a tunable bound state in the continuum(BIC)based on Fabry-Perot cavity is proposed in this work.Figure(a)shows the structural model of the designed Fabry-Perot cavity absorber,which consists of Ag as a substrate,a layer of the dielectric material Al_(2)O_(3) above the Ag substrate,and a high-refractive-index grating as the top dielectric layer Si ridge.By adjusting the thickness parameter d of Al_(2)O_(3),the transformation of BIC into q-BIC is achieved.Specifically,when d is increased from 273 nm to 298 nm,the BIC can be transformed into quasi-BIC,and the perfect absorption of the absorber in the continuum spectrum can be increased to 100%.In this work,the factors affecting the perfect absorption are explored by using the interference theory;theoretical calculations of the quasi-BIC are carried out by using the coupled mode theory and impedance matching theory;the physical mechanism of the BIC is explained by using the electric and magnetic field theory.The BIC is caused by the electric and magnetic dipole modes as well as the mirror image of the base Ag,which causes the interferential phase cancellation effect.Compared with the conventional absorber,the proposed absorber has excellent structural parameter robustness and a wide range of BIC modulation.More importantly,the absorber has excellent sensing performance with a maximum sensitivity of up to 34 nm/RIU and a maximum quality factor of 9.5.Last but not least,the absorber also achieves dual-frequency open-light performance,the maximum modulation depth and the minimum insertion loss of the dual-frequency switch reach 99.4%and 0.0004 dB,respectively.These findings have significant implications in the fields of photonics,optical communication,and sensor technology.

关 键 词：连续域束缚态 完美吸收 耦合模理论 传感 

分 类 号：TB34[一般工业技术—材料科学与工程]