Nonmechanical varifocal metalens using nematic liquid crystal

Abstract

Metalenses exhibit a substantial potential in replacing traditional optical component as they present a methodology for miniaturization. Lenses with tunable focal lengths can play a key role in various fields with applications in imaging, displays, and augmented and virtual reality devices. Here, we propose an electrically controllable varifocal metalens at the wavelength of 950 nm. The metasurface cascaded with nematic liquid crystal is integrated into an analog chip, which providing sequential specific two-dimensional addressable voltage patterns. The focal length of the reflective light can be modulated continuously with the change of voltage patterns. For the super-pixel cell with 6 μm period at a low voltage of 6 V, the zoom range and the zoom ratio are demonstrated to be 180 mm and 34, respectively. Besides, attributing to the enhanced forward scattering of Huygens metasurface and the large birefringence index of the liquid crystal, along with the integrated circuit compatible design, our metalens owns high integration in the NIR band under considering the practical processing. Therefore, the proposed nonmechanical varifocal metalens may unleash the full potential of continuous zoom metalens for micro-optical display and imaging applications in the future.

Keywords

• liquid crystal
• metasurface
• moiré lens
• nonmechanical
• varifocal