International audienc

Designing color pixels using plasmonic nanostructures and metasurfaces has become a luring area of research in recent years. Here, we experimentally demonstrated the voltage tunability of a dynamic plasmonic color filter by using an aluminum grating integrated with the nematic liquid crystal (LC). Along with a typical substrate coated with rubbed polyimide film, the aluminum grating itself serves as a molecular alignment layer to form a twisted LC cell. This hybrid structure allows electrically controlled transmission color by applying the voltage. A significant spectral tunability of such a device has been demonstrated by applying the small voltage from 0 to 4 V.

Polarization sensitive and insensitive color filters have important applications in the area of nano-spectroscopy and CCD imaging applications. Metallic nanostructures provide an efficient way to design and engineer ultrathin color filters. These nanostructures have capability to split the white light into fundamental colors and enable color filters with ultrahigh resolution but their efficiency can be restricted due to high losses in metals especially at the visible wavelengths. In this work, we demonstrate all-dielectric color filters based on Si nanoantennas, which are sensitive to incident-wave polarization and, thus, tunable with the aid of polarization angle variation. Two different information can be encoded in two different polarization states in one nanostructure. The nanoantenna based pixels are highly efficient and can provide high quality of colors, in particular, due to low losses in Si at optical frequencies. We experimentally demonstrate that a variety of colors can be achieved by changing the physical size of the nonsymmetric cross-shaped nanoantennas. The proposed devices allow to cover an extended gamut of colors on CIE-1931 chromaticity diagram owing to the existence of high-quality resonances in Si nanoantennas. Significant tunability of the suggested color filters can be achieved by varying polarization angle in both transmission and reflection mode. Additional tunability can be obtained by switching between transmission and reflection modes.

In this paper, we show that the phase shift of spin waves propagating in the plane of the film can be controlled by a metasurface formed by an ultra-narrow non-magnetic spacer separating edges of the two thin ferromagnetic films. We used this approach to demonstrate numerically the metalens for spin waves.

No abstract

No abstract

A very high efficiency Ultra wide band(UWB) hemispherical dielectric resonator antenna is simulated. The antenna is excited by commonly used feeding technique known as microstrip feeding. The dielectric resonator (DR) is inserted in the vertical edge of the substrate, which covers almost entire UWB bands(3.1 GHz to 10.6 GHz). A high impedance bandwidth of 3.74 GHz to 10.49 GHz is achieved in simulation. Compared to normal hemispherical dielectric resonator antenna, this design shows large volume reduction. A significant result analysis is also given in the paper.

In this paper, we show that the phase shift of the spin waves can be controlled by metasurface formed by an ultra-narrow non-magnetic spacer separating two thin ferromagnetic films. For this purpose, we exploit the strength of the exchange coupling of RKKY type between the films which allows to tune the phase of the transmitted spin waves in the wide range of angles [−π/2;π/2]. We combined the phase-shift dependency along the interface with the lens equation to demonstrate numerically the metalens for spin waves.