Numerical Study of a Polarization Selective Visual Optical Switch

The subwavelength structure based on metamaterial has been widely used in the application of structure color due to its unique characteristics. Here, a composite structure consisting of a circular hole and different number of metal strips is proposed. By changing the polarization direction of the incident light, the resonance peak in the visible light range shifts, and the material presents different colors. At the same time, take advantage of the shift of the resonance peak, a plasmonic optical switch, of which on/off states can be indicated by the structural color, is constructed, and the maximum contrast ratio is more than 20 dB. In addition, by means of changing the geometric parameters and materials of the metal strip, the colors presented basically cover the whole visible light range. This method theoretically proves the feasibility of using subwavelength structure to construct visual plasmonic optical switch using structural color in the visible light range, which provides a broad prospect for the application of multiple physical mechanism in nanostructure design.