关键词: 表面等离激元/
耦合/
宽带/
吸收
English Abstract
Broadband absorption caused by coupling of epsilon-near-zero mode with plasmon mode
Wang Dong,Xu Jun,
Chen Yi-Hang
1.School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China
Fund Project:Project supported by the Natural Science Foundation of Guangdong Province, China (Grant Nos. 2015A030311018, 2017A030313035).Received Date:06 June 2018
Accepted Date:25 July 2018
Published Online:20 October 2019
Abstract:Epsilon-near-zero mode provides a new path for tailoring light-matter interactions on a nanoscale because of its unique characteristics and ability to be used in many scientific fields. Among these applications, broadband absorption has aroused the considerable interest in photonic research. In this paper, we first show that the surface plasmon resonance is excited by the metal disk array structure without dysprosium-doped cadmium oxide nanolayer, and the structure achieves the local effect of light at a certain wavelength. In addition, in order to be able to use this new technique to achieve a broadband absorption, we take advantage of the surface plasmon resonance to excite the epsilonnear-zero mode which cannot be excited under normal incidence but has a very large density of states. Then, we show that over one order of magnitude increase in the absorption band of a periodically patterned metal-dielectric-metal structure can be obtained by integrating a dysprosium-doped cadmium oxide material into the insulating dielectric gap region. We analyze the absorption band at mid-infrared wavelength comprising plasmonic metamaterial resonators and epsilon-near-zero modes supported by dysprosium-doped cadmium oxide material. The two resonance modes lie in the weak coupling regime and achieve a 470 nm wideband light absorption. Finally, we perform numerical simulations by using the finite-difference-time-domain method to investigate the relationship between the epsilon-near-zero mode and the surface plasmon resonance mode. It is sure that the whole broadband mightily has the local effect of light. The epsilon-near-zero mode mainly is excited at the short wavelength of the broadband, and the surface plasmon resonance mode mainly focuses on long wavelength of the broadband. The simulation demonstrates that the two resonance modes are coupled to achieve a broadband absorption. Additionally, the dielectric constants are tunable by doping density, resulting in plasma frequency change, where the real part of the dielectric constant becomes zero at plasma frequency. Broadband absorption theoretically can be realized in any band of mid-infrared wavelength due to plasma frequency changing. Broadband absorption relaxes the single wavelength condition in previous absorption studies, and compared with the narrowband absorption, broadband absorption at present has many applications, such as in absorbers, sensors, filters, coherent thermal emitters, microbolometers, photodectors, solar cells, fingerprint recognition, energy harvesting devices, etc.
Keywords: plasmonic/
coupling/
wideband/
absorption
