Polarization-insensitive magnetically tunable perfect absorber for refractive index sensing applications

Abstract

In this paper, a polarization-insensitive magnetic tunable perfect metamaterial absorber is analyzed which shows its functionality as a refractive index (RI) sensor. The unit cell structure of reported absorber consists of a cross-shaped Indium Arsenide (InAs) array over aluminum ground plane and has dimensions less than [Formula: see text] with thickness of 7.5[Formula: see text][Formula: see text] and periodicity of 9[Formula: see text][Formula: see text] making it an ultra-thin absorber. The proposed absorber provides an average absorption of 99.99% on the implementation of magnetic field (B) at 0.4[Formula: see text]T. The resonance frequency and corresponding absorption rates can be controlled by varying the magnetic field from [Formula: see text]–0.4[Formula: see text]T which provides high absorption as well as shift in the frequency spectrum by 0.3[Formula: see text]THz/T. Additionally, parametric analysis has also been done to confirm the selection of the optimum value of the designed parameters of the structure. Furthermore, simulation results reveal that the proposed structure is very sensitive to the change of RI values in the surroundings thus, the proposed structure can be employed as a RI sensor high sensitivity of 1.083[Formula: see text]THz/RIU over the range of 1–1.6[Formula: see text]RI. In addition, the result shows that the sensor can detect different chemical compounds such as ethanol, gasoline, paraffin, sodium chloride, carbon disulfide with an average sensitivity of 0.925[Formula: see text]THz/RIU. Thus, the proposed absorber with obtained sensitivity can be utilized as a biochemical sensor, making it one of the best contenders for chemical industry uses in diagnosis of different hazardous chemicals as well as finding its applicability in biomedical uses.