Electrical Broad Tuning of Plasmonic Color Filter Employing an Asymmetric-Lattice Nanohole Array of Metasurface Controlled by Polarization Rotator

Abstract

Wide range of color change in nanohole array structure on a metal film have been successfully demonstrated using asymmetric-lattice design of nanoholes and an electrically switching polarization rotator. Recently, some studies have been reported that various color states were obtained in a single unit cell structure using extraordinary optical transmission (EOT) of nanopatterned structure, which could be one of the most important solutions for achieving ultrahigh integration density in optoelectronic devices. However, because they used the interfacial refractive index or dielectric constant as controlling factors for the color tuning, they were not capable of inducing a changeable range of color with different primary color states. To overcome this limitation, in this study, an asymmetric-lattice nanohole array design was integrated with an electrically controlled polarization rotator, employing a twisted nematic (TN) liquid crystal (LC). This simple structure of nanohole arrays with a rectangular lattice enabled mixed color states as well as precisely designed two different primary colors, by modulating the polarization of the incident light. The color-tuning shift was greater than 120 nm. Since the surface plasmonic (SP) modes on both sides, a top and a bottom interface, were matched better by the TN-LC layer assembled on the rectangular-lattice nanohole metal layer, the transmittance at the resonance peak wavelength was increased by 158% compared to that of the bare nanohole structure. The nanohole-array-on-metal-film simultaneously functions as an electrode, and this advantage, coupled with the low driving voltage of the TN-LC layer, can open new possibilities in applications to various optoelectronic device concepts.

Tunable topological valley transport in two-dimensional photonic crystals

“…Although our work focuses on the theoretical design of the tunable valley state excitations, it can also be achieved practically. As many previous works about the realization of tunable nano-devices based on the electro-optics effect of LCs [41,42], our proposed structures are also able to be fabricated with the help of modern nano- machining technologies. In addition, the special requirement for the excitation of valley states can be easily solved by using point-like chiral sources composed of four-antenna with proper phase lags and narrow Gaussian beams.…”

Sr‐induced color‐tunable and thermal stability enhancing in the phosphor (Ba1‐xSrx)9Lu2Si6O24:Eu2+ for solid‐state lighting

“…The corresponding luminescent decay curves can be fitted via an Equations:where I t and I 0 are the luminescence intensity at time of t and 0, τ 1 and τ 2 are the decay times for exponential components, respectively. The average lifetime values are calculated by:…”

Recent Progress in Active Optical Metasurfaces

“…The phase of an LC depends on several factors, including the chemical composition of its constituent molecules, its temperature, and critically, the local electrical/magnetic conditions. While some designs explicitly rely on changes in the temperature of the unit cell for tuning, most induce changes on the liquid crystal electrically by applying voltage or by irradiation, often UV . LC molecules will in general align with an impressed electric field, which allows for the material phase to be modified using an appropriately oriented external voltage or by illumination at a specific frequency and polarization.…”