The plasmon-induced transparency (PIT), which is destructive interference between the superradiation mode and the subradiation mode, is studied in patterned graphene-based terahertz metasurface composed of graphene ribbons and graphene strips. As the results of finite-difference time-domain (FDTD) simulation and coupled-mode theory (CMT) fitting, the PIT can be dynamically modulated by the dual-mode. The left (right) transmission dip is mainly tailored by the gate voltage applied to graphene ribbons (stripes), respectively, meaning a dual-mode on-tooff modulator is realized. Surprisingly, an absorbance of 50% and slow-light property of 0.7 ps are also achieved, demonstrating the proposed PIT metasurface has important applications in absorption and slow-light. In addition, coupling effects between the graphene ribbons and the graphene strips in PIT metasurface with different structural parameters also are studied in detail. Thus, the proposed structure provides a new basis for the dual-mode on-tooff multi-function modulators.

Articles you may be interested inState-selected imaging studies of formic acid photodissociation dynamics J. Chem. Phys. 132, 154306 (2010); 10.1063/1.3386576 CO product distribution from metastable levels of HCO X2 A' prepared by stimulated emission pumping J. Chem. Phys. 98, 5095 (1993); 10.1063/1.464966 Stateselected photodissociation dynamics of HONO(A1 A'): Characterization of the NO fragmentMetastable resonances on the ground electronic state of the HCO radical have been prepared by stimulated emission pumping. The resonances have energies 5000 to 10 000 cm Ϫ1 above the dissociation limit of HCO and can be assigned by their vibrational and asymmetric-top rotational character. The transition linewidths of the resonances and the rotational and vibrational distributions of the CO dissociation products have been measured. The linewidths show a strong dependence on the vibrational character of the resonance rather than a monotonic dependence on energy, and thus provide an important example of nonstatistical behavior. CO͑vϭ2͒ was produced in the decay of all six resonances studied, while only the three highest energy resonances produced measurable amounts of CO͑vϭ3͒. CO rotational distributions with population in low-J states, which often showed nonstatistical structure, were characteristic of the products from all the resonances studied. The rotational distributions depend both on the vibrational character of the parent state and on the rotational state prepared in the HCO. The experimental results are compared and contrasted with previous quantum mechanical calculations and analyzed in the context of a modified Franck-Condon model for the dissociation.

The van der Waals (vdW) heterostructure, made up of two dissimilar two-dimensional materials held together by van der Waals interactions, has excellent electronic and optoelectronic properties as it provides a superior interface quality without the lattice mismatch problem. Here, we report the development and photoresponse characteristics of a p-n diode based on a stacked black phosphorus (BP) and rhenium disulfide (ReS2) heterojunction. The heterojunction showed a clear gate-tunable rectifying behavior similar to that of the conventional p-n junction diode. Under UV illumination, the BP/ReS2 p-n diode displayed a high photoresponsivity of 4120 A W-1 and we were able to modify the photoresponse properties by adjusting the back gate voltage. Moreover, an investigation of various channel lengths yielded the highest photoresponsivity of 11 811 A W-1 for a BP length of 1 μm. These results suggested vdW 2D materials to be promising for developing advanced heterojunction devices for nano-optoelectronics.

Transition metal dichalcogenides (TMDs) have drawn great attention owing to their potential for electronic, optoelectronic and spintronics applications. In TMDS/ferromagnetic bilayers, efficient spin current can be generated by the TMDs for the manipulation of magnetic moment in the ferromagnetic layer. In this work, we report on the electric-field modulated spin-orbit torques (SOT) in WS2/NiFe (Py) bilayers by spintorque ferromagnetic resonance technique (ST-FMR). It is found that the RF current can induce a spin accumulation at WS2/Py interface due to the interfacial Rashaba-Edelstein effect. More importantly, the SOT ratio between field-like torque and anti-damping-like torque can be effectively controlled by applying back-gate voltage in WS2/ NiFe bilayers.