The terahertz metamaterials for sensitive biosensors in the detection of ethanol solutions

• Published in: Optics communications Vol. 475; p. 126287
• Main Authors: Li, Fuyu, He, Ke, Tang, Tingting, Mao, Yinghui, Wang, Rui, Li, Chaoyang, Shen, Jian
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2020
• Subjects: Ethanol solutions; Metamaterials; Refractive index; Sensing; Terahertz; Sensing; Metamaterials; Ethanol solutions; Terahertz; Refractive index
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2020.126287

Metamaterials have attracted much attention due to their subwavelength characteristics, especially in the field of unlabeled refractive index sensing. Because biomolecular molecules have special biological fingerprint spectra in terahertz band, high sensitivity sensor components can be realized by using the special electromagnetic response of metamaterials. In this paper, a novel biosensor based on electromagnetic induced reflection is designed. We find that the asymmetrically fractured double-ring resonator can effectively enhance the fano-resonance of electromagnetic induction reflection, where the resonance position occurs at 1.57 THz. Oscillating Lorentz model shows that when the resonant detuning continues to increase, the bright mode and the dark mode are strongly coupled. When the light mode decreases, the radiation loss also decreases, which induces the decrease of resonance ability. The sensitivity of pure ethanol solution (analyte) under 5μm coating thickness is 103.7 GHz/RIU, 107.1 GHz/RIU and 112.05 GHz/RIU, respectively. The sensitivity and full width at half maximum (FWHM) of the sensor are studied from the perspectives of analyte concentration, thickness, and proportion, respectively. The results show the great potential of electromagnetic metamaterials as sensitive sensors in biological solution detection. •We design a new biosensor with asymmetric double-ring resonator to realize the electromagnetic induced resonance.•The mechanism of EIR-like phenomena is explained by the Lorentz model, in which the light mode and the dark mode generate coupling interference.•We evaluate the performance of the proposed refractive index sensor. The sensitivity of pure ethanol solution is 103.7 GHz/RIU, 107.1 GHz/RIU and 112.05 GHz/RIU, respectively.•This work shows the great potential of metamaterials as sensitive sensors in biological solution detection.