Two key metrics for imaging systems are their magnification and optical bandwidth. While high-quality imaging systems today achieve bandwidths spanning the whole visible spectrum and large changes in magnification via optical zoom, these often entail lens assemblies with bulky elements unfit for size-constrained applications. Metalenses present a methodology for miniaturization, but their strong chromatic aberrations and the lack of a varifocal, achromatic element limit their utility. Although exemplary broadband achromatic metalenses are realizable via dispersion engineering, in practice, these designs are limited to small physical apertures as large area lenses would require phase compensating scatterers with aspect ratios infeasible for fabrication. Many applications, however, necessitate larger areas to collect more photons for better signal-to-noise ratio and furthermore must also operate with unpolarized light. In this paper, we simultaneously achieve achromatic operation at visible wavelengths and varifocal control using a polarization-insensitive, hybrid optical–digital system with area unconstrained by dispersion-engineered scatterers. We derive phase equations for a pair of conjugate metasurfaces that generate a focused accelerating beam for chromatic focal shift control and a wide tunable focal length range of 4.8 mm (a 667-diopter change). Utilizing this conjugate pair, we realize a near spectrally invariant point spread function across the visible regime. We then combine the metasurfaces with a postcapture deconvolution algorithm to image full-color patterns under incoherent white light, demonstrating an achromatic 5× zoom range. Simultaneously achromatic and varifocal metalenses could have applications in various fields including augmented reality, implantable microscopes, and machine vision sensors.

中文翻译：

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可见光与四面亚表面的同时消色差和变异静脉成像

成像系统的两个关键指标是其放大倍率和光带宽。尽管当今的高质量成像系统通过光学变焦实现了跨越整个可见光谱的带宽和放大倍率的大变化，但这些通常需要具有体积大的元件的镜头组件，不适合尺寸受限的应用。Metalenses提供了一种用于小型化的方法，但是其强大的色差和缺乏变焦，消色差元件限制了其实用性。尽管可以通过色散工程来实现示例性宽带消色差金属透镜，但实际上，这些设计仅限于较小的物理孔径，因为大面积透镜将需要相位补偿散射体，且纵横比对于制造而言是不可行的。但是，许多应用程序 需要更大的区域来收集更多的光子，以获得更好的信噪比，而且还必须在非偏振光下工作。在本文中，我们使用偏振不敏感的混合光数字系统，同时在不受散射工程散射体限制的区域内，同时实现了在可见波长处的消色差操作和变焦控制。我们导出了一对共轭超颖表面的相位方程，这些共轭超颖表面产生了聚焦的加速光束，用于彩色焦移控制和4.8 mm（667屈光度的变化）的宽可调焦距范围。利用该共轭对，我们在可见光范围内实现了近光谱不变的点扩散函数。然后，我们将超表面与捕获后的反卷积算法结合起来，以在不相干的白光下成像全彩色图案，展示了5倍消色差变焦范围。同时消色差和变焦金属感镜可以在各种领域中应用，包括增强现实，可植入显微镜和机器视觉传感器。