Electrically tunable terahertz switch based on superconducting subwavelength hole arrays.

We experimentally demonstrate an electrically tunable superconducting device capable of switching the extraordinary terahertz (THz) transmission. The planar device consists of subwavelength hole arrays with real-time control capability. The maximum transmission coefficient at 0.

Optimization for nonmagnetic concentrator with minimized scattering.

Based on the generalized transformation for a nonmagnetic cylindrical concentrator, we present nonlinear coordinate transformations to realize excellent concentrating performance with minimized scattering. By matching the impedance at both the inner and outer boundaries and utilizing nonlinear optimization techniques, the best parameters of the nonlinear transformation can be determined. Results show that the concentrating power is sensitive to the impedance at the inner interface.

Cylindrical optimized nonmagnetic concentrator with minimized scattering.

By using optimized transformation function, we research on a minimized scattering nonmagnetic concentrator, which can realize impedance matching at the inner and the outer boundaries. It has been demonstrated that the optimized transformation function method can improve the concentrating performance remarkably. The cylindrical anisotropic shell can be mimicked by radial symmetrical sectors which alternate in composition between two profiles of isotropic dielectrics, and the permittivity in each sector can be properly determined by the effective medium theory.

Tunable photonic bandgap in a one-dimensional superconducting-dielectric superlattice.

The transmittance of one-dimensional photonic crystals consisting of superconductor and lossless dielectric has been systematically studied through the transfer-matrix method. Obviously, the shift of the photonic bandgap (PBG) becomes more noticeable by adjusting the thicknesses of the dielectric layers than that of superconductor layers. Furthermore, the number of PBGs can be controlled by varying the thicknesses of dielectric layers.