# Polarization tunable all-dielectric color filter based on cross-shaped Si nanoantennas

## TL;DR

This paper introduces polarization-sensitive all-dielectric Si nanoantenna color filters that are tunable and highly efficient, enabling high-resolution color encoding with low losses compared to metallic nanostructures.

## Contribution

It presents a novel all-dielectric color filter design using cross-shaped Si nanoantennas that are tunable via polarization angle, offering high efficiency and extended color gamut.

## Key findings

- Achieved tunable color filtering by varying nanoantenna size and polarization.
- Demonstrated high-quality colors with low-loss dielectric nanoantennas.
- Extended color gamut on CIE-1931 chromaticity diagram.

## Abstract

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 Si nanoantennas based all-dielectric color filters, 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 a single physical nanostructure. The nanoantenna based pixels are highly efficient and can provide high quality of colors due to low losses in dielectric 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 cover an extended gamut of colors on CIE-1931 chromaticity diagram due to the existence of high quality resonance in Si nanoantennas. The device shows significant tunability of color while operating this color filter device in transmission as well as in reflection mode.