A split-OK shaped resonator based metamaterial absorber for high performance terahertz sensing of microfluids

Abstract In this study, a terahertz (THz) metamaterial sensing device (MMSD) with a highly effective absorption mechanism and remarkable sensitivity for fluid analysis is developed for accurate detection of microfluids. The multilayered design of the MMSD includes a silicon substrate with a thin metallic reflector, a microfluidic channel, a resonator with split-OK shaped design, and a surface layer over the resonator. The MMSD is designed for optimal THz wave interaction. A comprehensive study on the sensing performance is conducted by evaluating the absorbance, reflectance, transmittance, and resonance shift under various conditions. We achieve a near-perfect absorption of 99.99% through a numerical analysis in the 1–3 THz region. The THz MMSD exhibits resonance at 1.682 THz with a notch depth of −42 dB. A sensitivity of 980 GHz RIU −1 is obtained from the resonance shift by varying the refractive index of the microfluidic channel. A Q-factor of 20.56 highlights the sensor’s accuracy and reliability in detecting small changes in liquid characteristics. One distinctive feature of this structure is the split-OK shaped resonator, which enhances the wave control and interaction of THz waves to provide outstanding performance. With its creative and effective design, this study demonstrates the potential of the sensor for use in biomedical diagnostics, natural observation, liquid quality assessment, and the development of THz sensing technology.