Metamaterial Electromagnetic Wave Absorbers (Adv. Mater. 23/2012)

Ultrabroadband Plasmonic Absorber for Terahertz Waves

“…The Ohmic loss origin of this plasmonic absorber stands in contrast with the losses due to the interlayer dielectric in conventional terahertz metamaterials absorbers composed of the metal/dielectric/metal structure. [ 23 ] Since the structure is fourfold symmetric, it can be expected that the absorber is polarization insensitive for terahertz waves of normal incidence. We further characterized the angle-dependent response of the designed plasmonic absorber.…”

“…First, the fabrication technology to create this structure is well established, and this aspect is also readily integrated into silicon-based optical systems. Compared with existing terahertz absorbers, [ 23 ] our device is ultrabroadband, is also polarization insensitive, and can sustain absorption at large incidence angles.…”

“…[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Metamaterial absorbers typically consist of two coupled metallic layers separated by a dielectric spacer to create electric and magnetic responses for impedance matching with free space. [ 23 ] The electric response can be obtained from excitation of the top metal layer readily coupled to an external electric fi eld, while the magnetic response is provided by pairing the top layer with a metal ground plane or metal wire for an external magnetic fi eld. In the microwave and terahertz regions, these metamaterial absorbers obtain high absorption through dielectric loss and impedance matching at resonance.…”

“…In the microwave and terahertz regions, these metamaterial absorbers obtain high absorption through dielectric loss and impedance matching at resonance. [ 23 ] The absorption frequency range and amplitude can be tuned by adjusting the shape, size, thickness, and properties of the metallic structure and dielectric spacer. Due to the nature of resonance response, these metamaterial absorbers usually exhibit narrowband absorption that has advantages in applications such as fi ltering, sensing, and modulation.…”

A Large‐Area, Mushroom‐Capped Plasmonic Perfect Absorber: Refractive Index Sensing and Fabry–Perot Cavity Mechanism

“…[ 12,14 ] The MPA is a recently developed branch of metamaterial which exhibits nearly unity absorption within certain frequency range. [15][16][17][18][19][20] The optically thin MPA possesses characteristic features of angular-independence, high Q -factor and strong fi eld localization that have inspired a wide range of applications including electromagnetic (EM) wave absorption, [ 17,21,22 ] spatial [ 20 ] and spectral [ 19 ] modulation of light, [ 23 ] selective thermal emission, [ 23 ] thermal detecting, [ 24 ] and refractive index sensing for gas [ 25 ] and liquid [ 12,14 ] targets. The MPA is typically comprised of three layers: a metallic resonator's layer, e.g., cross-type resonators, [ 23,26 ] split-ring resonators, [ 17 ] or metallic nanoparticles, [ 27 ] and a highly refl ective layer, e.g., metallic fi lm [ 17,23,26,27 ] or metallic mesh grid, [ 17 ] separated by a subwavelength-thick dielectric fi lm (spacer).…”