Measurement of Aspheres and Free-Form Surfaces with the Tilted-Wave-Interferometer
Measurement of Aspheres and Free-Form Surfaces with the Tilted-Wave-Interferometer
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使用倾斜波干涉仪测量非球面和自由曲面
DOI：
10.1007/978-3-642-36359-7_10
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
W. Osten
中科院分区：
文献类型：
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作者：
G. Baer;J. Schindler;C. Pruss;W. Osten
近年来，在高性能光学领域，非球面已成为首选的解决方案。与球面元件相比，非球面元件的优点是光学设计的自由度大大增加。这样可以更好地校正像差，同时减少了满足给定设计目标所需的元件数量，从而能够构建更紧凑的光学系统，同时具有更高的光学性能。由于这些令人信服的优势，非球面光学广泛应用于最先进的光学系统，从智能手机微型相机成像系统等大众产品开始，一直到光刻或空间应用中使用的高端光学系统。如果非球面的旋转对称性被打破，在设计中甚至可以达到更多的自由度。这种不需要显示任何对称性的自由曲面可以用来进一步提高光学系统的性能。一种可能性是构建这样的系统，其中元素不再沿直线排列，而是将光轴折叠起来。通过利用这种设计选项，可以开发非常紧凑的系统，对机械和热影响也不太敏感。离轴系统的另一个优点，可以实现与自由形式的元素是避免反射，经常发生在镜头的中心，在一个经典的系统。这对于具有相干源的应用程序尤其重要。此外，如果没有任何可接受吸收的光学折射率材料，某些波长需要使用反射光学而不是透镜。为了避免中心遮挡，这里最简单的方法是使用无反射镜。这种光学系统的一个例子是将用于下一代半导体制造的EUV光刻技术。
In the area of high performance optics aspherical surfaces have become the solution of choice over the past years [1] [2]. The advantage of aspherical, compared to spherical elements, is the highly increased degree of freedom for the optics design. This allows better correction of aberrations, by simultaneously reducing the number of elements needed to fulfill a given design target, enabling the construction of more compact optical systems, with higher optical performance at the same time. As a result of these convincing advantages aspherical optics are widely used in state of the art optical systems, starting from mass products like imaging systems for micro cameras in smartphones, reaching to high end optical systems used in lithography or space applications. Even more degrees of freedom in the design can be reached, if the rotational symmetry of the aspheric surface is broken. Such free-form surfaces that do not have to show any symmetry at all can be used to further improve the performance of an optical system. One possibility is the construction of systems where the elements are no longer arranged along a straight line, but where the optical axis is folded. By taking advantage of this design option it is possible to develop very compact systems, which also are less sensitive to mechanical and thermal influences. Another advantage of off-axis systems that can be realized with free-form elements is the avoidance of reflexes that often occur at the center of the lens in a classical system. This is especially important for applications with coherent sources. Further, certain wavelengths demand the usage of mirror optics instead of lenses, if there aren’t any optical refractive materials with tolerable absorption available. To avoid central obscurations, here again the easiest way is to use free-from mirrors. One example for this kind of optical systems is the EUV lithography that will be used in the next generation of semiconductor fabrication.