Ultra Thin Highly Sensitive Metamaterial Absorber Based Refractive Index Sensor for Detecting Adulterants in Alcohol
Sagnik Banerjee, Ishani Ghosh, Mazed Billah Fahad, Santosh Kumar Mishra, Rahul Yadav, Bhargav Appasani
Abstract
This research provides a unique design of a terahertz-frequency metamaterial absorber. The absorber shows resonance at frequency 5.01 THz where the peak absorption is 99.5%. A staggering quality factor of 125.25 is also discovered. Since the radiation is non-ionizing, the metamaterial absorber can function as a refractive index sensor and can be used for sensing applications. To support the chosen design parameter values, parametric analysis was performed. The resonance mechanism has been clearly explained using the surface current distribution plot, and the metamaterial nature of the sensor has also been justified using the impedance plot, followed by the plot showing the permeability and permittivity at the resonance frequency. By detecting changes in the refractive index of the surrounding medium, the proposed sensor finds application in detecting the percentage of water and percentage of methanol in alcohol solution. Methanol and water are two prominent contaminants of alcohol. It can detect the percentage of water in alcohol with a sensitivity of 2.105 THz/RIU and can detect percentage of methanol in alcohol with a sensitivity of 1.999 THz/RIU. This work can inspire future research on using THz metamaterial absorbers for quality assessment of food products and beverages.