Virtual Polarizer: Coherent Perfect Ultrawideband Polarization Control of Chiral Electromagnetic Waves

In this paper, a novel concept, virtual polarizers (VP), have been proposed through the principles of coherent perfect absorption (CPA) and coherent perfect transparency (CPT) for chiral electromagnetic waves (EWs) to enable polarization control. By interacting and interfering with the signal and control waves, the VP achieves ultra-wideband polarization control for EWs. A structure that implements the VP effect is proposed, realizing polarization control of chiral EWs. The incident polarized waves under consideration have their electric field aligned parallel to the x-y plane. These EWs can be separated into two polarized waves: transverse electric (TE) waves and transverse magnetic (TM) ones, with components directed along the x -axis and y -axis, respectively. Transparent propagation is achieved in the 0~2.31 THz band due to CPT, while ultra-wideband coherent perfect polarization conversion is achieved in the 2.72~8.41 THz (102%) band. Through the modulation of InSb layers, VP can realize the perfect control of chirality of phase difference and polarization form of EWs with high polarization conversion efficiency for its arrangement of PT-symmetric structure and implement alteration of the EW propagation. Moreover, the stability of the external parameters is also discussed and considered.