Active Spectral Absorption Control in a Tunable Liquid Crystal/Metamaterial Structure by Polarization Plane Rotation

Access full text - https://doi.org/10.1007/978-3-030-31866-6_58We present theoretical studies conducted on the newly-introduced controllable metamaterial-liquid crystal system. Our model consists of a standard metamaterial single cell split ring resonator array with dimensions tailored to match a desired frequency in the infrared frequency regime, with an added liquid crystal layer, in order to control the refractive index surrounding the resonator array. We show that this type of system can show controllable spectral absorption in the desired range, making them suitable for a range of optical applications

INFLUENCE OF POLARIZING ELECTRIC FIELDS ON THE ELECTRICAL AND OPTICAL PROPERTIES OF POLYMER–CLAY COMPOSITE SYSTEM

We examined the electrical and optical properties of a new material containing polymer–clay nano-composite dispersed in a nematic liquid. The clay (Cloisite-type) was modified by copolymerization of maleic anhydride and divinyl benzene, using azobisisobutytironitrile as the initiator. The final polymer–clay nano-composite has an intercalated structure according to XRD patterns. We measured the thermally stimulated depolarization currents and determined the activation energies. Simultaneously we measured the optical transmission and we studied the influence of the previously applied polarizing electric fields. </jats:p

Dynamics of Cyanophenyl Alkybenzoate molecules in a surface layer adsorbed onto Aerosil. I. Cyanophenyl Hexylbenzoate

A composite prepared from aerosil A380 and the liquid crystal (LC) 4-hexyl-4'-cyanophenyl benzoate (CP6B) was investigated by broadband dielectric spectroscopy in a large temperature range. The selected high silica density (ca. 7 g aerosil/1 g of CP6B) allows the observation of a thin layer (two-monolayer structure) adsorbed on the surface of the silica particles. For the composite one relaxation process is observed at frequencies much lower than that of the processes found for bulk CP6B. It is assigned to the dynamics of the molecules in the surface layer. The temperature dependence of its relaxation rates obeys the Vogel-Fulcher-Tammann law, which is characteristic for glass-forming liquids. The quasi 2D character of the observed glassy dynamics in the surface layer is discussed. The temperature dependence of the CP6B relaxation in the composite is compared with that of related hexylcyanobiphenyl molecules in the surface layer of aerosil composite with a similar concentration