Focus-tunable lenses are indispensable to optical systems. This paper proposes an electrically modulated varifocal metalens combined with twisted nematic liquid crystals. In our design, a metalens is employed to focus on different points depending on the polarization state of incident light. We demonstrated that the varifocal metalens has a sub-millisecond response time. Furthermore, the numerical aperture of both the first and second focal points can be customized to achieve a wide range of 0.2–0.7. Moreover, the full width at half maximum approached the diffraction limit at multiple focal points. Because of the advantages of our proposed electrically modulated metalens, it has the potential for application in optical technology and biomedical science, both of which require high image quality and a rapid response time.

中文翻译：

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电调制的变焦金属元与扭曲向列液晶结合

可调焦镜头是光学系统必不可少的。本文提出了一种与扭曲向列液晶相结合的电调制变焦金属。在我们的设计中，根据入射光的偏振态，采用金属元素聚焦在不同的点上。我们证明了变焦金属元具有亚毫秒级的响应时间。此外，可以对第一和第二焦点的数值孔径进行自定义，以实现0.2-0.7的宽范围。而且，半峰全宽在多个焦点处接近衍射极限。由于我们提出的电调制金属素的优点，它具有在光学技术和生物医学领域的应用潜力，这两者都需要高图像质量和快速响应时间。