Ultrabroadband absorber based on single-sized embedded metal-dielectric-metal structures and application of radiative cooling

Abstract

The realization of ultrabroadband absorption is a fundamental part of a thermal emitter, especially in the application of radiative cooling. This study involved proposing and systematically analyzing a novel structure termed as an embedded metal-dielectric-metal (EMDM) structure. The results in the case of an individual resonator indicated that the EMDM resonator displayed a broader full width at half maximum (FWHM) that was 1.9 times that of the metal-dielectric-metal (MDM) resonator due to mode matching at the terminated end and enhanced scattering intensity. With respect to the case of periodic resonators, single-sized periodic EMDM resonators are employed to achieve a broader FWHM that is 3.8 times that of the MDM resonators. In addition, a strong coupling effect is confirmed between localized MDM and hybrid modes. An application of lossy-dielectric based periodic three-dimensional EMDM resonators indicated that an average absorptivity of 0.85 in the entire atmospheric window (8-13 μm). The results revealed the potential of EMDM structures for radiative cooling devices and other ultrabroadband absorbers.

Metal-Insulator-Metal-Based Plasmonic Metamaterial Absorbers at Visible and Infrared Wavelengths: A Review

“…The shape of the corners and the sidewall angles have an important role in defining single and multiband resonances [ 56 ]. The end shape of the micropatch produces the difference of optical modes formed in the middle dielectric layer because MIM structures can be considered as waveguides and the shape of the waveguide end defines the waveguide mode [ 57 ]. The first three micropatch shapes are symmetric in the x and y directions, and absorption occurs at a single wavelength.…”

“…The strategies of multi-band and broadband absorption are classified into three groups: asymmetrically-shaped [ 47 , 52 , 85 , 86 , 87 , 88 , 89 ] or multi-size [ 42 , 65 , 66 , 90 , 91 , 92 , 93 , 94 ] micropatches, multi-layers of MIM structure [ 95 , 96 , 97 , 98 , 99 , 100 ], and embedded in dielectric materials [ 57 , 101 , 102 ]. The first two are based on multi-resonance that produces multi-mode absorption.…”

“…Broadband absorption is also achieved by MIM-PMAs with single or multi-layers embedded in lossy dielectrics such as amorphous Si [ 57 ] and SiN [ 101 ]. The resonances of MIM-PMAs can be broadened by lossy materials, which results in broad absorption.…”

Metamaterial-Based Radiative Cooling: Towards Energy-Free All-Day Cooling

“…Aluminum-doped zinc dioxide was selected for its properties as a transparent conducting oxide that can achieve a plasmonic response in the IR region (Figure 3h). More recently, Hervé et al [57] and Liu et al [58] created designs to control the thermal emission spectrally and directionally using gratings that can regulate the surface phonon-polariton resonance. The focus was on the thermal control of gratings on multi-layer structures that consist of boron nitride (BN), SiC, and SiO 2 [57] (Figure 3i).…”

Active metamaterial nearly perfect light absorbers: a review [Invited]

“…The narrowband metal perfect absorbers are of particular interest in sensing [48], imaging [49], thermal emitting [50], and color filter applications [51,52]. On the other hand, their broadband counterparts have potential applications in thermal photovoltaics [53], radiative cooling [54], hot electron-based photodetectors [55], photochemistry [56], and efficient solar vapor/steam generation [57]. However, having a passive response may impose some limits on the operational bandwidth and thus the functionality of the metamaterial light absorbers.…”