摘要
Recent breakthroughs in the field of non-Hermitian physics present unprecedented opportunities,from fundamental theories to cutting-edge applications such as multimode lasers,unconventional wave transport,and high-performance sensors.The exceptional point,a spectral singularity widely existing in non-Hermitian systems,provides an indispensable route to enhance the sensitivity of optical detection.However,the exceptional point of the forementioned systems is set once the system is built or fabricated,and machining errors make it hard to reach such a state precisely.To this end,we develop a highly tunable and reconfigurable exceptional point system,i.e.,a single spoof plasmonic resonator suspended above a substrate and coupled with two freestanding Rayleigh scatterers.Our design offers great flexibility to control exceptional point states,enabling us to dynamically reconfigure the exceptional point formed by various multipolar modes across a broadband frequency range.Specifically,we experimentally implement five distinct exceptional points by precisely manipulating the positions of two movable Rayleigh scatterers.In addition,the enhanced perturbation strength offers remarkable sensitivity enhancement for detecting deep-subwavelength particles with the minimum dimension down to 0.001λ(withλto be the free-space wavelength).
基金
supported by the National Natural Science Foundation of China(Grant Nos.61871215,61771238,and 61701246)
the National Key Research and Development Program of China(Grant No.2022YFA1404903)
the Fund of Qing Lan Project of Jiangsu Province(Grant No.1004-YQR22031)
the Six Talent Peaks Project in Jiangsu Province(Grant No.2018-GDZB-009)
the Fund of Prospective Layout of Scientific Research for NUAA(Nanjing University of Aeronautics and Astronautics)(Grant Nos.1004-ILA22002 and 1004-ILA22068)
the Research and Practice Innovation Program of Nanjing University of Aeronautics and Astronautics(Grant No.xcxjh20210408)
the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX22_0364)
the Fundamental Research Funds for the Central Universities,NUAA(Grant No.NS2023022)
the Nanjing University of Aeronautics and Astronautics Startup Grant(Grant No.1004-YQR23031)
the Distinguished Professor Fund of Jiangsu Province(Grant No.1004-YQR24010)
Fundamental Research Funds for the Central Universities,NUAA(No.NE2024007)
the Singapore National Research Foundation Competitive Research Program(NRF-CRP22-2019-0006).
