Ultra-broadband metamaterial absorbers from long to very long infrared regime

Abstract

Broadband metamaterials absorbers with high absorption, ultrathin thickness and easy configurations are in great demand for many potential applications. In this paper, we first analyse the coupling resonances in a Ti/Ge/Ti three-layer absorber, which can realise broadband absorption from 8 to 12 μm. Then we experimentally demonstrate two types of absorbers based on the Ti/Ge/Si3N4/Ti configuration. By taking advantage of coupling surface plasmon resonances and intrinsic absorption of lossy material Si3N4, the average absorptions of two types of absorbers achieve almost 95% from 8 to 14 μm (experiment result: 78% from 6.5 to 13.5 μm). In order to expand the absorption bandwidth, we further propose two Ti/Si/SiO2/Ti absorbers which can absorb 92% and 87% of ultra-broadband light in the 14–30 μm and 8–30 μm spectral range, respectively. Our findings establish general and systematic strategies for guiding the design of metamaterial absorbers with excellent broadband absorption and pave the way for enhancing the optical performance in applications of infrared thermal emitters, imaging and photodetectors.

Design and Fabrication of Substrate-Free Au/SiNx/Au Metafilm for THz Sensing Application

“…The absorber features a metalinsulator-metal (MIM) configuration. To better understand the measured response, numerical calculations based on the finite integration method were used to simulate the EM response [16,35,36]. The periodic nature of the MFPA structures enables the simulation to be performed in a unit cell with the appropriate boundary conditions.…”

Thin Multispectral Camouflage Absorber Based on Metasurfaces with Wide Infrared Radiative Cooling Window

“…Many efforts have been dedicated to developing multispectral compatible camouflage techniques, which is a challenge and trend in electromagnetic wave control, such as the stealth of the helicopter engine intake and exhaust system and the surface ship chimney part. [1][2][3] With regard to the active working mode of microwave detectors, the radar camouflage materials possess high absorptivity and low reflectivity. [4][5][6][7][8] On the contrary, to evade the detection of infrared detectors, the infrared camouflage materials equipped with low infrared emissivity, which means low absorptivity and high reflectivity, are demanded IR Herein, a hierarchical metamaterial (HMM) is reported to achieve multispectral camouflage for thermal infrared detectors and radar.…”

Broadband Sound Insulation and Dual Equivalent Negative Properties of Acoustic Metamaterial with Distributed Piezoelectric Resonators

“…However, the actual focus began in 2000, when Smith [ 5 ] demonstrated a composite medium that exhibits a frequency region in the microwave regime with simultaneously negative values of effective permeability and permittivity. Since then, artificially constructed metamaterials have achieved unprecedented development in the fields of electromagnetics [ 6 , 7 , 8 ], optics [ 9 , 10 , 11 ], mechanics [ 12 , 13 , 14 ], and acoustics [ 15 , 16 , 17 ].…”