Physics

Geology

Poynting vector

Gallium arsenide

Opacity

Molar absorptivity

Resonator

Terahertz radiation

Magnetic field

Optics

Absorption (acoustics)

Figure of merit

Metamaterial

Tunable metamaterials

Oceanography

Materials science

Substrate (aquarium)

Quantum mechanics

Refractive index

Metamaterial absorber

Optoelectronics

Split-ring resonator

Results in Physics

We numerically propose and demonstrate an ultra-narrow perfect metamaterial absorber (PMA) for refractive index sensing applications in the terahertz region. The designed PMA is only composed of a gallium arsenide (GaAs) cross-shaped resonator array on an opaque copper/silicon substrate. Simulated results show that the proposed PMA can achieve a near-perfect absorption peak with an absorptivity of 99.49% and a high quality factor value of 637 at 2.44THz. The physical mechanism of the narrow absorption is explained by the electric field, magnetic field and Poynting vector distributions. As a refractive index sensor, its sensitivity and figure of merit reach up to 1.94THz/refractive index unit (RIU) and 506RIU−1, respectively. These results make the proposed PMA to have great potential in detecting, imaging and sensing applications.

Ultra-narrow-band terahertz perfect metamaterial absorber for refractive index sensing application