作为常见的偏振光学元件之一的波片, 如1/4波片、1/2波片和全波片, 被广泛应用于高数值孔径(NA)成像系统(偏光显微镜和浸没式光刻机)的偏振检测技术中。随着系统NA的日益增大, 正确分析和精确计算大角度斜入射光波经过波片后产生的相位延迟变得至关重要。目前的分析方法主要是基于电磁波传播理论和光线追迹法两种。由于前人在使用上述两种方法时, 不仅计算过程较为复杂, 没有最终表达式, 而且计算结果存在较大的差异。首先推导波片中e光波法线的折射率表达式, 然后再推导e光光线的折射率表达式, 最后分别利用电磁波传播理论和光线追迹法导出斜入射光波通过波片后的o光与e光之间的相位延迟。计算结果显示, 利用这两种方法得到的相位延迟最终表达式完全一致。准确地描述了波片的相位延迟特性, 为波片的设计和误差分析提供了严格的理论依据, 具有重要的理论意义和应用价值。

As one common polarization components, the waveplate (λ/4 plate, λ/2 plate and 0λ plate) is widely used in polarimetry of high-NA imaging systems (microscope and immersion scanner). With increasing NA of the system, the accurate analysis and calculation of the retardation with respect to oblique incidence become significant. At present, there are two methods to analyze this quantity, one is based on the theory of wave propagation and the other is based on the ray-tracing method. Due to the retardation solved by some authors based on above two methods is not only so complicated without final expression, but also the final results exist much difference. First, the expressions on the two refractive indices of e-ray wave-normal and actual e-ray are reduced. Then, the retardation between e-ray and o-ray is formulated in which oblique incidence passing through the waveplate, using the theory of wave propagation and ray-tracing method respectively. As a result, the final expressions of retardation deduced by above two methods are consistent. The retardation property of the waveplate is described accurately, the rigorous theory basis is supplied for the design and error analysis of the waveplate, and it has important theoretical significance and application value.