Achieving broad absorption band and high incident angles by stochastically-distributed oblique-flat-sheet metamaterial perfect absorbers

Abstract

In this work, we integrated a periodic seed layer and oblique deposition method to fabricate a stochastically-distributed oblique-flat-sheet metamaterial perfect absorber (MPA). Such design could increase its absorption bandwidth and tolerance to high angle-incidence due to the fact that various oblique flat sheets offer different resonance conditions while even a single oblique flat sheet could provide different optical paths for resonance. On the other hand, a seed layer could reduce uncertainty regarding to direct oblique deposition and provide abilities to manipulate the bandwidth of the MPA. We also setup a simulation model in the aids of Visual Basic Application and examined the absorption behavior of the MPA under TM and TE oblique incidence that could achieve high absorbance under 80° and 60° incidence, respectively. Finally, in measurement, the fabricated sample owns 65% absorbance within 80–250 THz and over 90% absorbance within 250–320 THz at x-polarization normal incidence; as for the y-polarization normal incidence, we could achieve overall 70% absorbance within 80–300 THz. The measured results reveal similar tendency compared to the simulated ones.

Multiband Terahertz Metamaterial Perfect Absorber for Microorganisms Detection

“…The highest absorption coefficient is obtained for an open book-type metastructure, where oblique sheets offer the ability to manipulate the bandwidth of MPA leading to different resonance conditions and different optical paths for resonances 38 . Sensor parameters of an open book-type metastructure are optimized as: periodicity (P) = 70µm, substrate thickness (t s ) = 15µm, width of metal stripes (w s ) = 4.5µm, length of metal stripes (L s ) = 50µm, gap between the metal stripes (G) = 40µm, the thickness of ground metallic plane (t m ) = 0.08µm, length(L) and width(w) of the open book resonator = 20µm and 15µm, g = 5µm respectively.…”

A Monopole-Based Wideband Absorber for Ultralarge Angles

“…around 80° oblique angles) are still challenging. Recently some literature sheds light on that [17]- [19]. Nevertheless, measurement under such ultra-large angles brings further difficulties.…”

“…Some structures are designed especially for large incident scenarios, such as oblique-flat-sheets [17] and folded resistive patches [18]. Simulated results suggest good performance, but measurements under normal incidence are merely given in [17], [18].…”

“…Some structures are designed especially for large incident scenarios, such as oblique-flat-sheets [17] and folded resistive patches [18]. Simulated results suggest good performance, but measurements under normal incidence are merely given in [17], [18]. The characteristic mode (CM) analysis is employed in [19], in which a broadband absorption is achieved within 82° oblique incidence for transverse magnetic (TM) polarization and 45° for transverse electric (TE) one.…”