摘要
Searching for an optimal solution among many nonunique answers provided by transformation optics is critical for many branches of research,such as the burgeoning research on invisibility cloaks.The past decades have witnessed rapid development of transformation optics,and different kinds of invisibility cloaks have been designed and implemented.However,the available cloaks realized thus far have been mostly demonstrated with reduced parameters,which greatly impact the predefined cloaking performance.Here,we report a general design strategy to realize full-parameter omnidirectional cloaks that can hide arbitrarily shaped objects in free space.Our approach combines a singular transformation with transformation-invariant metamaterials.The cloaking device with extreme parameters is implemented using a metallic array structure.In the experiment,two cloak samples are designed and fabricated,one with nondiscrete cloaking regions and the other with separated hidden regions.Near-unit transmission of electromagnetic waves with arbitrary incident angles is experimentally demonstrated along with significantly suppressed scattering.Our work challenges the prevailing paradigms of invisibility cloaks and provides deep insight into how transformation optics could be harnessed to obtain easily-accessible metadevices.
基金
sponsored by the Key Research and Development Program of the Ministry of Science and Technology(Grants Nos.2022Y FA1404704,2022YFA1405200,and 2022YFA1404902)
the National Natural Science Foundation of China(Grant No.61975176)
the Key Research and Development Program of Zhejiang Province(Grant No.2022C01036)
the Fundamental Research Funds for the Central Universities
the work at Nanyang Technological University was sponsored by Singapore Ministry of Education(Grant No.MOE2018-T2-2-189(S))
A*Star AME IRG Grant(Grant No.A20E5c0095)
Programmatic Funds(Grant No.A18A7b0058)
National Research Foundation Singapore Competitive Research Program(Grant Nos.NRF-CRP22-2019-0006 and NRF-CRP23-2019-0007).
