Apfel J H
Appl Opt. 1981 Mar 15;20(6):1024-9. doi: 10.1364/AO.20.001024.
When multilayer reflectors are used at nonnormal incidence, the two planes of polarization generally have different phase shifts. This difference, known as phase retardance, depends on the multilayer design, the incidence angle, and the wavelength. Heretofore, the design of reflectors with specific phase retardance has been carried out by computer optimization except for the case of a single layer on a metal substrate. A graph of phase retardance D vs the average phase shift A as a function of layer thickness provides a means for visualization that is useful in reflector designs. A D-A graph predicts the phase properties of a reflector as a function of the index and thickness of an added layer. Graphs of phase retardance vs average phase for two different materials can be superposed to predict the composite performance of a multilayer reflector. This graphical technique is employed to design and analyze reflectors with specified phase retardance.
当多层反射器在非垂直入射情况下使用时，两个偏振平面通常具有不同的相移。这种差异，即所谓的相位延迟，取决于多层结构设计、入射角和波长。迄今为止，除了金属基板上的单层情况外，具有特定相位延迟的反射器设计都是通过计算机优化来进行的。作为层厚度函数的相位延迟D与平均相移A的关系图提供了一种可视化手段，这在反射器设计中很有用。D-A图预测了反射器的相位特性作为添加层的折射率和厚度的函数。两种不同材料的相位延迟与平均相位的关系图可以叠加起来，以预测多层反射器的复合性能。这种图形技术被用于设计和分析具有指定相位延迟的反射器。
