Ferroelectric nanofibers with an embedded optically nonlinear benzothiazole derivative

We report measurements of the molecular first hyperpolarizability, thermal stability, photophysical, piezoelectric and ferroelectric properties of a benzothiazole derivative bearing an arylthiophene π-conjugated bridge both in solution and when embedded into a poly (L-lactic acid) (PLLA) matrix in the form of electrospun fibers with an average diameter of roughly 500 nm. The embedded nanocrystalline phenylthienyl-benzothiazole derivative, with crystal sizes of about 1.4 nm resulted in a good piezoelectric response from these functionalized electrospun fibers, indicative of a polar crystalline structure.Fundação para a Ciência e a Tecnologia (FCT

Reduction of orbital angular momentum radio beam divergence using a 3D printed planar graded index lenses

This paper shows that the range of an Orbital Angular Momentum (OAM) radio link can be at least doubled by using a 3D graded index lens to reduce beam divergence. This is a major step towards realizing practical high capacity OAM radio links using cheap, compact and light weight lenses

Reduction of orbital angular momentum radio beam divergence using a 3D printed planar graded index lenses

This paper shows that the range of an Orbital Angular Momentum (OAM) radio link can be at least doubled by using a 3D graded index lens to reduce beam divergence. This is a major step towards realizing practical high capacity OAM radio links using cheap, compact and light weight lenses

Manufacture of electrical and magnetic graded and anisotropic materials for novel manipulations of microwaves.

Spatial transformations (ST) provide a design framework to generate a required spatial distribution of electrical and magnetic properties of materials to effect manipulations of electromagnetic waves. To obtain the electromagnetic properties required by these designs, the most common materials approach has involved periodic arrays of metal-containing subwavelength elements. While aspects of ST theory have been confirmed using these structures, they are often disadvantaged by narrowband operation, high losses and difficulties in implementation. An all-dielectric approach involves weaker interactions with applied fields, but may offer more flexibility for practical implementation. This paper investigates manufacturing approaches to produce composite materials that may be conveniently arranged spatially, according to ST-based designs. A key aim is to highlight the limitations and possibilities of various manufacturing approaches, to constrain designs to those that may be achievable. The article focuses on polymer-based nano- and microcomposites in which interactions with microwaves are achieved by loading the polymers with high-permittivity and high-permeability particles, and manufacturing approaches based on spray deposition, extrusion, casting and additive manufacture