Measurement of Large Freeform Optics using a Small and High-Precision Sensor

使用自由曲面光学，光学工业可以提供紧凑、高效和高性能的光学产品，这些产品具有许多独特的功能，可以减少光学系统中透镜的数量和尺寸。这些产品具有广泛的应用，包括科学研究，太阳能收获，医疗和军事应用。然而，由于缺乏有效的测量方法来测量制造过程中和之后的自由曲面光学表面，今天的自由曲面光学制造依赖于“试错”方法。该奖项支持基础研究，以提供开发新的自由曲面光学测量系统所需的知识，该系统可以有效地测量自由曲面光学表面。新的测量系统将为美国公司提供竞争优势，并可能导致电信、航空航天、消费电子、汽车和医疗行业的创新。新的自由曲面光学测量是基于子孔径测量，使用一个小而高精度的夏克-哈特曼波前传感器。然后将这些测量结果结合使用新颖的拼接方法来重建整个自由曲面光学表面。第一个研究目标是建立各种拼接方法对系统设计的依赖关系。每一种拼接方法都有其收敛速度和相应的残差。设计参数包括孔径大小、形状和泽尼克多项式项的选择。为了实现这一目标，在阿尔瓦雷斯透镜上的实验将通过在全孔径的10- 100%之间改变子孔径大小来进行。此外，将测试方形和球形子孔径，实验将使用多达7个Zernike多项式项。第二个研究目标是建立系统动态性能与Shack-Hartmann传感器中微透镜设计和透镜阵列配置之间的关系。在实验研究中，微透镜参数（包括f值和透镜几何形状）和透镜阵列配置（包括非均匀透镜布局和微透镜所在的任意基曲线）会发生变化；系统的动态性能将根据坡度变化程度、测量时间和测量精度进行评估。

Using freeform optics, the optical industry can provide compact, efficient, and high performance optical products with many unique features that allow reduction in both the number and size of lenses in an optical system. These products have wide applications including scientific research, solar energy harvest, medical, and military applications. However, manufacturing of freeform optics today relies on the "trial and error" approach due to the lack of efficient metrology to measure freeform optical surfaces during and after they are manufactured. This award supports fundamental research to provide knowledge that is needed to develop a new freeform optics measurement system that can measure freeform optical surfaces efficiently. The new measurement system will provide US companies a competitive edge and can lead to innovations in telecommunication, aerospace, consumer electronics, automotive, and medical industries.The new freeform optical metrology is based on subaperture measurements using a small and high-precision Shack-Hartmann wavefront sensor. These measurements are then combined using novel stitching methods to reconstruct the entire freeform optical surface. The first research objective is to establish the dependence of each stitching method on the system design. Each stitching method will be characterized by its convergence rate and corresponding residual error. The design parameters include aperture size, shape, and selection of Zernike polynomial terms. To achieve this objective, experiments on an Alvarez lens will be performed by changing the subaperture size between 10-100 percent of the full aperture. In addition, a square and a sphere shape subaperture will be tested, and up to 7 Zernike polynomial terms will be used in the experiments. The second research objective is to establish the relationship between the dynamic performance of the system and microlens design and lens array configuration used in the Shack-Hartmann sensor. In experimental investigations, microlens parameters (including f-number and lens geometry) and lens array configuration (including non-uniform lens layout and arbitrary base curve where the microlenses reside) will be varied; dynamic performance of the system will be evaluated in terms of degree of slop change, measurement time, and measurement accuracy.