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.

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We analyzed a transient blinking phenomenon in a fringe-field switching liquid crystal (LC) mode that occurred at the moment of frame change even in the optimized DC offset condition for minimum image flicker. Based on the positional dynamic behaviors of LCs by using a high-speed camera, we found that the transient blink is highly related to the asymmetric responses of the splay-bend transitions caused by the flexoelectric (FE) effect. To remove the transient blink, the elastic property adjustment of LCs was an effective solution because the FE switching dynamics between the splay-enhanced and bend-enhanced deformations are highly dependent on the elastic constants of LCs, which is the cause of momentary brightness drop.

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