Tungsten based anisotropic metamaterial as an ultra-broadband absorber

Yinyue Lin, Yanxia Cui, Fei Ding, Kin Hung Fung, Ting Ji, Dongdong Li, Yuying Hao

Research output: Journal article publicationJournal articleAcademic researchpeer-review

42 Citations (Scopus)

Abstract

� 2017 Optical Society of America. We show theoretically that an array of tungsten/germanium anisotropic nano-cones placed on top of a reflective substrate can absorb light at the wavelength range from 0.3 μm to 9 μm with an average absorption efficiency approaching 98%. It is found that the excitation of multiple orders of slow-light resonant modes is responsible for the efficient absorption at wavelengths longer than 2 μm, and the anti-reflection effect of tapered lossy material gives rise to the near perfect absorption at shorter wavelengths. The absorption spectrum suffers a small dip at around 4.2 μm where the first order and second order slow-light modes get overlapped, but we can get rid of this dip if the absorption band edge at a long wavelength range is reduced down to 5 μm. The parametrical study reflects that the absorption bandwidth is mainly determined by the filling ratio of tungsten as well as the bottom diameter of the nano-cones and the interaction between neighboring nano-cones is quite weak. Our proposal has some potential applications in the areas of solar energy harvesting and thermal emitters.
Original languageEnglish
Pages (from-to)606-617
Number of pages12
JournalOptical Materials Express
Volume7
Issue number2
DOIs
Publication statusPublished - 1 Jan 2017

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

Cite this