Design of liquid crystal metalens for achromatic full-color imaging with multiplexed phase coding

Abstract

Liquid crystals metalens (LC-ML) has attracted much attention due to its powerful functions in shaping light field with planar structure and its great application potentials. However, LC-MLs usually suffer from large chromatic aberration resulting from high phase dispersion. Here, we propose and demonstrate achromatic imaging at red-green-blue (RGB) wavelengths 450 nm, 526 nm, and 630 nm with optimized wavelength multiplexed phase coding in a single liquid crystals metalens. The optimized wavelength multiplexed phase coding, which works on three operating wavelengths simultaneously, is introduced via the complex field of summation of the individual optical fields at selected RGB wavelength and can be achieved via photo-patterning an azo-dye doped LC. The optical efficiency of the fabricated achromatic liquid crystals metalens can be optimized by applying appropriate voltages. The proposed achromatic LC-ML at multi-wavelengths is easy to fabricate and has a potential application in the display field.