A Highly Sensitive Ultra-Miniaturized Refractive Index based Metamaterial Terahertz BioSensor

A novel highly sensitive ultra miniaturized refractive index based metamaterial terahertz sensor for biomedical application is proposed in this study. The suggested design has footprint of 0.248 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{\lambda}_{\boldsymbol{eff}}$</tex> × 0.248 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{\lambda}_{\boldsymbol{eff}}$</tex> where <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{\lambda}_{\boldsymbol{eff}}$</tex> represent the wavelength corresponding to 4.06 THz. The sensor can have an absorptivity of 99.97%. The proposed sensor shows excellent angular stability and is polarization independent due to the symmetric nature of the structure. The performance of the sensing device is being evaluated by changing both, the analyte's thicknesses and refractive indexes. Further, performance parameters are calculated for the biological samples. The results indicate a sensitivity of 0.732 THz/RIU on average, a quality factor higher than 20.1, and a figure of merit (FoM) greater than 3.79. Hence, the proposed design can be considered suitable for sensing, including nucleic acids and cancer detection.