Superior analogs for electromagnetically induced transparency (EIT) and absorption (EIA) in metasurfaces (MSS) are universal, but fewer integrate both effects in one device, let alone contribute to polarization manipulations. Here, note that asymmetrical EITs are rigorously demonstrated under both polarization incidences in dielectric orthogonal dumbbell‐shaped structures, with a maximum group delay of 335 ps. The transverse magnetic (TM) mode excited EIT holds a transparent window at 1.318 THz close to the transverse electric (TE) mode excited that of 1.358 THz, which triggers the linear‐to‐circular polarization conversion at 1.339 THz with an optimized transmittance of 0.67, validated via the axial ratio. Additionally, asymmetrical EIAs are presented with an embedded metal‐phase VO2 plate, holding a common absorption of 0.51 at 1.340 THz, of which the insulating state affects little to the circular‐polarization output. Given the detuning of two frequencies (1.339 and 1.340 THz) can be compensated by the dispersion properties, it can be understood as the original converted circularly polarized propagating light decays with 0.5‐absorption via phase‐tuned VO2, operating as a temperature‐driven switch. The circular‐polarization transmission and absorption are integrated respectively based on EIT and EIA with the different states of VO2, promising broad prospects in multifunctional devices.

In this paper, a photoexcited multitasking Janus metasurface (MJM) based on the phase‐changed material vanadium dioxide and the photosensitive materials silicon and germanium in the terahertz (THz) region is proposed, which also exploits the directionality feature of electromagnetic waves. The MJM can switch its functionalities between working band shifting and full‐space polarized wave control, and six functions can be implemented by exciting the switchable materials. By regulating the power of the incident pump beam, it is feasible to complete band adjustment in terms of normal incidence, i.e. the band range of polarization conversion ratio >0.9 changing from 1.23 THz–1.91 THz to 0.98 THz–1.91 THz in the reflection state and axial ratio (AR) <3 dB band range toggling between 0.69 THz–1.08 THz and 0.67 THz–0.96 THz in the transmission state. However, for the backward incidence,, it presents reflective linear‐to‐circle (LTC) polarization conversion (PC), with AR <3 dB domain of 0.99 THz–1.63 THz. The multiple reflection interference theory and electric field distributions are introduced to interpret the high performance. Moreover, the designed device exhibits a high angular tolerance for achieving LTC PC. The integration of numerous functions in a single structure endows the MJM with the great benefit for efficient polarization‐controlled applications.

In this paper, an innovative multitasking device (MTD) regulated by the gravity field realizing the functions of metamaterial absorber (MMA) and linear polarization converter (LPC) is proposed and theoretically investigated. When the device operates in the function of MMA, the engineered SRR structure offers robust conditions for the formation of anapole mode. The anapole mode can lead to destructive interference in the far‐field and constructive interference within the configuration synchronously; thereby, the incident wave energy can be consumed strongly. It is verified that the proposed MTD in the MMA state can acquire a high absorption rate exceeding 0.9 from 10.82 to 13.55 GHz, with a broad relative bandwidth (RBW) of 22.4%. While in the LPC state, the utilization of the “L”‐shaped structure successfully introduces an equivalent magnetic resonance to achieve the translation of the incident wave polarization state. In this case, the orthogonal state of the incident beam can be obtained by the MTD with the polarization conversion ratio (PCR) over 0.9 in the range of 2.62–3.72 GHz, whose RBW is 34.7%. The design accomplishes the functional combination of MMA and LPC through the gravity field regulation, simultaneously staggering the operating bands to guarantee their independence and anti‐interference.

Metastructure analogs of electromagnetically induced transparency (EIT) provide a new approach for engineering realizations of nonlinear optical manipulations regardless of harsh conditions; further can be employed in polarization conversions for its low-loss transmission and phase modulation. In this work, dual-band EIT in a dielectric-metal hybrid metasurface achieved via providing different coupling channels is theoretically investigated with a maximum group delay of 404 ps. The linear-to-circular polarization conversion (LCPC) behaviors are observed respectively holding the transmittance of 0.58 at 0.68 THz, 0.73 at 0.76 THz, 0.61 at 0.90 THz, 0.53 at 0.99 THz, owning to the asymmetric EIT responses in the transverse magnetic (TM) and transverse electric (TE) modes incidence. On the other hand, phase-transition VO2 is doped to perturb the dark mode resonances. With its conductivity σ = 105 S/m, dual transparency peaks transform into unimodal broadband transmission windows with relative bandwidths of 17.1% and 9.1% under the TE and TM excitations apart. Induced LCPC possesses a bandwidth of 10.4% centered at 0.76 THz attributed to the drastic dispersion. The as-proposed design exploits pattern asymmetry of EIT responses to realize LCPC, promising the wide prospect of reconfigurable multiplexings.

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