Ultrabroadband Absorption Enhancement via Hybridization of Localized and Propagating Surface Plasmons

Abstract

Broadband metamaterial absorbers (MAs) are critical for applications of photonic and optoelectronic devices. Despite long-standing efforts on broadband MAs, it has been challenging to achieve ultrabroadband absorption with high absorptivity and omnidirectional characteristics within a comparatively simple and low-cost architecture. Here we design, fabricate, and characterize a novel compact Cr-based MA to achieve ultrabroadband absorption in the visible to near-infrared wavelength region. The Cr-based MA consists of Cr nanorods and Cr substrate sandwiched by three pairs of SiO2/Cr stacks. Both simulated and experimental results show that an average absorption over 93.7% can be achieved in the range of 400–1000 nm. Specifically, the ultrabroadband features result from the co-excitations of localized surface plasmon (LSP) and propagating surface plasmon (PSP) and their synergistic absorption effects, where absorption in the shorter and longer wavelengths are mainly contributed bythe LSP and PSP modes, respectively. The Cr-based MA is very robust to variations of the geometrical parameters, and angle-and polarization-insensitive absorption can be operated well over a large range of anglesunder both transverse magnetic(TM)- and transverse electric (TE)-polarized light illumination.

Broadband absorption of monolayer MoS2 in visible region using a tetramerized nanorod metasurface

“…The absorption of total structure of the TNM can be simplified as A _total (λ) = 1-R(λ) due to the optically thick Ag substrate, where R is the reflection of the structure. In order to calculate the absorption distributions from different parts of the TNM, the power dissipation density of the structure can be expressed as [23,30]:…”

“…However, as shown in figure 5(c), although broadband absorption features can be maintained even the height h of the Ag nanorods are significantly altered, the average absorption of the monolayer MoS 2 will be dropped to 50.4% if h is reduced to 15 nm. This is because that the decrease of h will increase the coupling of the surface plasmons between the top and bottom surfaces of the Ag nanorods [30,40], the absorption efficiency of the monolayer MoS 2 will be degraded if h is too small. the thickness of the spacer, but the absorption efficiency will decrease obviously if t is too small.…”

Metamaterials‐Based Photoelectric Conversion: From Microwave to Optical Range

“…[113][114][115][116] Likewise, the multiband, polarization-insensitive, wide-angle, and tunable absorption can also be realized in the plasmonic MMs for optical applications. [117][118][119][120][121][122][123][124] For instance, a triple-band MM absorber working in the near-IR range was proposed in 2020 (Figure 6f). [117] The top layer is a nano-cuboids array composed of two pairs of metallic wires and a metallic block, in which each exhibits different resonance frequency, leading to the triple-band absorption.…”

Plasmonic photothermal properties of silver nanoparticle grating films

“…Simultaneous localized surface plasmon and propagating surface plasmon systems have been reported in various applications such as photovoltaic devices, 22,23 water splitting systems, 24,25 photoelectrochemical sensors, 26 broadband absorption enhancement, 27,28 and other applications. 29–31 Because a highly enhanced electric field can be obtained by the synergistic effect of both plasmon excitations, these devices showed significant improvement in their performance.…”