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In this paper, an ideal highly sensitive THz biological sensor based on a polarization-insensitive graphene absorber with three bands is designed and optimized. The concept of a polarization-insensitive sensor involves a ring of graphene and eight symmetrical ring resonators. Finite element modeling reveals that the developed absorber may be fine-tuned for a sensing capacity and an absorption efficiency of over 99.8 %. At frequencies of 3.769 THz, 5.888 THz, and 9.453 THz, respectively, three distinct narrow absorption peaks with efficiencies of 98.6 %, 99.2 %, and 99.8 % are produced as a result of field confinement induced by graphene surface plasmon resonances. This study delineates our sensitive refractive index sensor, including circular micro ring resonator and multiple graphene rings. A periodic design consisting of a center ring and eight peripheral rings that rotate π/4 rad produces a three-band absorber arrangement independent of wave polarization. Moreover, it has been demonstrated that modifying the graphene layer’s chemical potential may change the resonance frequencies while improving absorber performance. A maximum sensitivity of 3045 GHz/RIU, a Q-factor of 26.01, and a figure-of-merit of 9.18 RIU −1 are achieved by the proposed refractive index sensor with an analyte thickness of 2.3 μm. The suggested THz RI sensor offers an identical response for TE and TM polarizations because of its rotational symmetry. The performance of RI sensors is assessed using two biological samples: breast cancer and healthy breast cells. The findings unequivocally demonstrate the THz sensor’s possible biological applications. Achieving high absorption and sensitivity is the main feature of this paper.
Veisi et al. (Mon,) studied this question.