Polarization angle tailored multitasking metasturcure: electromagnetically induced transparency, electromagnetically induced absorption, linear-to-circular polarization conversion

Abstract

In this work, simultaneous implementation of electromagnetically induced transparency (EIT), electromagnetic induced absorption (EIA), and linear-to-circular polarization conversion (LTCPC) in the terahertz band is proposed in a metasturcture (MS) associated with tailoring the polarization angle (θ). The linear polarization (LP) waves with different θ can trigger different phenomena. EIT can be achieved with the incidence of transverse electric (TE) waves (θ = 0°), transverse magnetic (TM) waves (θ = 90°) cause the appearance of EIA, while a LP wave with θ = 45° induces the appearance of the LTCPC phenomenon. For TE waves, the EIT transparent window accompanied by the slow light effect has emerged from 0.288 to 0.797 THz, where the maximum group delay has arrived at 2.51 ps. For TM waves, an absorption peak of EIA is observed at 0.497 THz. The LTCPC phenomenon is well obtained with θ = 45° at 0.399 and 0.634 THz, where the transmission coefficient highly reaches 0.571 and 0.650. The optimal axis ratios (ARs) of LTCPC are 2.08 dB at 0.389 THz and 2.18 dB at 0.634 THz, respectively. Noteworthy, the two-oscillator and circuit models are adopted for the theoretical analysis of the EIT and EIA, and the conclusions obtained are in general agreement with the simulation results.