In the last 10 years, freeform optics has enabled compact and high-performance imaging systems. This article begins with a brief history of freeform optics, focusing on imaging systems, including marketplace emergence. The development of this technology is motivated by the clear opportunity to enable science across a wide range of applications, spanning from extreme ultraviolet lithography to space optics. Next, we define freeform optics and discuss concurrent engineering that brings together design, fabrication, testing, and assembly into one process. We then lay out the foundations of the aberration theory for freeform optics and emerging design methodologies. We describe fabrication methods, emphasizing deterministic computer numerical control grinding, polishing, and diamond machining. Next, we consider mid-spatial frequency errors that inherently result from freeform fabrication techniques. We realize that metrologies of freeform optics are simultaneously sparse in their existence but diverse in their potential. Thus, we focus on metrology techniques demonstrated for the measurement of freeform optics. We conclude this review with an outlook on the future of freeform optics.

中文翻译：

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成像自由光学

在过去的十年中，自由形式的光学技术已实现了紧凑而高性能的成像系统。本文从自由形式光学的简要历史开始，重点是成像系统，包括市场的兴起。这项技术的发展受到了明确机遇的推动，该机遇使科学能够在从极端紫外线光刻到空间光学的广泛应用中得到广泛应用。接下来，我们定义自由形式的光学器件并讨论并行工程，该工程将设计，制造，测试和组装整合到一个过程中。然后，我们为自由形式的光学和新兴的设计方法奠定了像差理论的基础。我们描述制造方法，重点是确定性计算机数控研磨，抛光和金刚石加工。下一个，我们考虑了中空频率误差，这些误差是由自由形式的制造技术固有产生的。我们认识到，自由形式光学的计量学同时存在，但数量稀少，但潜力无限。因此，我们将重点放在为自由曲面光学测量而论证的计量技术上。我们以对自由形式光学的未来展望展望结束本次审查。