title: Achieving an ultra-narrow multiband light absorption meta-surface via coupling with an optical cavity.
abstract: Resonant plasmonic and metamaterial absorbers are of particular interest for applications in a wide variety of nanotechnologies including thermophotovoltaics, photothermal therapy, hot-electron collection and biosensing. However, it is rather challenging to realize ultra-narrow absorbers using plasmonic materials due to large optical losses in metals that inevitably decrease the quality of optical resonators. Here, we theoretically report methods to achieve an ultra-narrow light absorption meta-surface by using photonic modes of the optical cavities, which strongly couple with the plasmon resonances of the metallic nanostructures. Multispectral light absorption with absorption amplitude exceeding 99% and a bandwidth approaching 10 nm is achieved at the optical frequencies. Moreover, by introducing a thick dielectric coupling cavity, the number of absorption bands can be strongly increased and the bandwidth can even be narrowed to less than 5 nm due to the resonant spectrum splitting enabled by strong coupling between the plasmon resonances and the optical cavity modes. Designing such optical cavity-coupled meta-surface structures is a promising route for achieving ultra-narrow multiband absorbers, which can be used in absorption filters, narrow-band multispectral thermal emitters and thermophotovoltaics.
authors.affiliation: Provincial Key Laboratory of Nanomaterials and Sensors, Institute of Optoelectronic Materials and Technology, College of Physics and Communication Electronics, Provincial Key Laboratory of Optoelectronic and Telecommunication, Jiangxi Normal University, Nanchang 330022, People's Republic of China.
authors.forename: Zhengqi
authors.initials: Z
authors.lastname: Liu
authors.forename: Guiqiang
authors.initials: G
authors.lastname: Liu
authors.forename: Xiaoshan
authors.initials: X
authors.lastname: Liu
authors.forename: Shan
authors.initials: S
authors.lastname: Huang
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Pingping
authors.initials: P
authors.lastname: Pan
authors.forename: Mulin
authors.initials: M
authors.lastname: Liu