Tunable Polarization-Multiplexed Achromatic Dielectric Metalens

Abstract

Tunable metasurfaces provide a compact and efficient strategy for optical active wavefront shaping. Varifocal metalens is one of the most important applications. However, the existing tunable metalens rarely serves broadband wavelengths restricting their applications in broadband imaging and color display due to chromatic aberration. Herein, an electrically tunable polarization-multiplexed achromatic metalens integrated with twisted nematic liquid crystals (TNLCs) in the visible region is demonstrated. The phase profiles at different wavelengths under two orthogonal polarization channels are customized by the particle swarm optimization algorithm and matched with the dielectric metaunits database to achieve polarization-multiplexed achromatic performance. By combining the broadband linear polarization conversion ability of TNLC, the tunability of varifocal achromatic metalens is realized by applying different voltages. Further, the electrically tunable customized dispersion-manipulated metalens and switchable color metaholograms are demonstrated. The proposed devices will accelerate the application of metasurfaces in broadband zoom imaging, AR/VR displays and spectral detection.

Metalens in Improving Imaging Quality: Advancements, Challenges, and Prospects for Future Display

“…Additionally, achromatic metalens design can be achieved by mixing spatial multiplexing, polarization multiplexing, filtering, and other capabilities. [165,166] In 2021, as shown in Figure 14 (e), Li et al integrated a multiple-layer bandpass filter with achromatic metalens and used the filter to screen RGB three visible waves. The metalens can realize achromatic function in wide band only by designing the phase required by the three waves achromatic.…”

A Holographic Broadband Achromatic Metalens

“…Optical lenses, indispensable components in optical systems, are typically limited by the chromatic aberration caused by the dispersion for wide bandwidths. [1,2] In terms of traditional refractive imaging lenses, the spatial distribution of the constructed dielectric material refractive index determines the deflection of the incident light. Since the refractive index of the dielectric material is related to the wavelength, the behavior of focus inevitably shows "positive dispersion."…”

“…Optical lenses, indispensable components in optical systems, are typically limited by the chromatic aberration caused by the dispersion for wide bandwidths. [ 1,2 ] In terms of traditional refractive imaging lenses, the spatial distribution of the constructed dielectric material refractive index determines the deflection of the incident light. Since the refractive index of the dielectric material is related to the wavelength, the behavior of focus inevitably shows “positive dispersion.” Generally, the method of reducing chromatic aberration is distinct dispersion complementation, including the achromatic doublet (triplet) of different glass‐based materials [ 3,4 ] and the hybrid diffractive–refractive achromatic lens.…”

Tailoring Group Delay Dispersion of Spatial Phaser using Anisotropic Metasurface and Polarized Incident Waves

“…Reconfigurable phasers are highly demanded to meet multifunctional processing in ASP applications. Based on some articles, [33,34] polarization-controlled metasurfaces can be used to increase the degree of freedom.…”