Perrin Guy
J Opt Soc Am A Opt Image Sci Vis. 2024 Apr 1;41(4):708-713. doi: 10.1364/JOSAA.518345.
The polarizing properties of optical systems are often characterized by their action on specific polarization states. For example, half-wave plates are used to rotate linear polarizations and quarter-wave plates to turn a linear polarization into an elliptical polarization and into a circular polarization if the linear polarization makes a 45° angle with the slow and fast axes of the quarter-wave plate. Phase shifts introduced by the optical train of an interferometer may lead to coherence losses and the existence of neutral axes-in the sense of linear polarizations whose polarization state is not modified by the optical system-is then of importance to maximize the fringe contrast. Neutral axes do not systematically exist. The purpose of this paper is to investigate how this notion can be generalized to define generalized neutral axes for optical systems. Generalized neutral axes are defined as linear polarizations whose polarization state is not modified by the optical system except for their orientation. It is shown that such generalized neutral axes exist for some classes of optical systems. The scheme proposed in this paper has quasi-unitary Jones matrices to give an approximate description of optical systems when generalized neutral axes do not exist. To the best of my knowledge, this formalism is a new scheme to describe the polarizing properties of nondepolarizing optical systems.
光学系统的偏振特性通常通过其对特定偏振态的作用来表征。例如，半波片用于旋转线偏振，而四分之一波片则用于将线偏振转换为椭圆偏振，并且如果线偏振与四分之一波片的慢轴和快轴成45°角，则可将其转换为圆偏振。干涉仪的光学系统引入的相移可能会导致相干性损失，并且中性轴（从偏振态不受光学系统改变的线偏振的意义上来说）的存在对于最大化条纹对比度很重要。中性轴并非总是存在。本文的目的是研究如何将这个概念推广，以定义光学系统的广义中性轴。广义中性轴被定义为偏振态除方向外不受光学系统改变的线偏振。结果表明，对于某些类型的光学系统存在这样的广义中性轴。当不存在广义中性轴时，本文提出的方案具有准幺正琼斯矩阵，以对光学系统进行近似描述。据我所知，这种形式体系是描述非退偏振光学系统偏振特性的一种新方案。
