Abstract-Temperature‐mediated excitation of defect modes in a periodic structure at terahertz frequencies

Roberta De Simone,  Francesco Chiadini,  Antonio Scaglione,  Vincenzo Fiumara,

https://onlinelibrary.wiley.com/doi/abs/10.1002/mop.32485

The dependence on temperature of a defect mode of a periodic dielectric multilayer is studied in the terahertz range by using the characteristic matrix method. The structure analyzed is composed of alternating layers of silica and polymethylpentene. The material of the defect is the indium antimonide (InSb), which has a permittivity that is temperature dependent causing a blueshift of the defect mode as the temperature rises. Although at terahertz frequencies, the InSb is a dissipative material, choosing appropriately the thickness of the defect results in a defect mode with a transmittance that, throughout the range explored, always remains above 0.9 with a maximum of 0.9914.

Abstract-Bicontrollable Terahertz Metasurface with Subwavelength Scattering Elements of Two Different Materials

Francesco Chiadini, Akhlesh Lakhtakia

https://arxiv.org/abs/1711.06343

Transmission of a normally incident plane wave through a metasurface with bicontrollable subwavelength scattering elements was simulated using a commercial software. Some pixels comprising the $H-shaped scattering elements were made of a magnetostatically controllable material whereas the remaining pixels were made of a thermally controllable material, the metasurface designed to operate in the terahertz spectral regime. The co-polarized transmission coefficients were found to exhibit stopbands that shift when either a magnetostatic field is applied or the temperature is increased or both. Depending on spectral location of the stopband, either the magnetostatic field gives coarse control and temperature gives fine control or vice versa. The level of magnetostatic control depends on the magnetostatic-field configuration.