Dual Mode Terahertz Cross Polarization Converter Based Pesticide Sensor

In this article, simultaneous total polarization conversion in both reflection and transmission modes is achieved in the frequency spectrum of 15.674–19.618THz and 10.802–12.542THz with peak conversion efficiencies of approximately 78% and approximately 64%, respectively, using an inclined <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Phi $ </tex-math></inline-formula>-shaped metallic pattern and split ground plane. In the frequency range of 16.37–18.168 THz, the total polarization conversion efficiency is >90%. Surface currents and electric field distributions are provided for the physical mechanism study of both polarization transformations. Using the suggested polarization converter’s reflection mode, the refractive indices of several pesticides are determined with a maximum percentage error of 0.29% and a peak sensitivity of 4.27THz/RIU. The proposed polarization converter’s bifunctional polarization conversion characteristic indicates its appropriateness for multifunctional and multifrequency polarization controller applications.