消色差的1/4波长延迟器的几何光学设计

THE GEOMETRIC DESIGN OF AN ACHROMATIC 1/4 WAVELENGTH RETARDER

在许多光谱学测量和实验研究中 ,常需要一个消色差 1 / 4波长延迟器来满足各种实验测量条件 .这可以通过一个在工作波长范围内折射率变化较小的菱型棱镜来实现 .为了使用方便 ,在光学系统中可设计一个具有三个全内反射面的 V型棱镜 ,其总的相位延迟达90°,同时可避免光路偏差 .在实际应用中 ,需对棱镜的尺寸和通光孔径进行优化设计 ,以达到最佳效果 .在本文中 ,我们给出了具有这种结构的几何设计例子 ,还结合不同参量成功地设计研制了一个消色差的 1 / 4波长延迟器 ,并应用于磁光材料的克尔效应测量中 .文中给出了详细计算和误差修正 ,所给出的计算公式可用于其他尺寸的消色差 1 / 4波长器的设计和研制 .

In many optical experimental systems for spectrum measurements,an achromatic 1/4 wavelength retarder is needed to satisfy experiment condition.This can be fulfilled by using a rhomb prism which has a nearly constant refractive index in the working wavelength range.To make the easy use of the prism in the optical system and to avoid the problem of central beam deviation,one type of the prism having three total internal reflection faces can be designed to have the total retarding angle equal to 90°.Though the angle can be relatively easily calculated in principle,the size and optical opening window of the prism are set by the optimization design.In this paper,we will give a few examples of geometric design by taking different size parameters into consideration.We have made the prisms and put them into the application of measuring the magneto optical Kerr ellipticity with success.Detailed calculation and error reduction in the design are also given.