Opt Express. 2023 May 8;31(10):16460-16470. doi: 10.1364/OE.490093.
This work presents a novel optical system for polarization image processing using geometric-phase (Pancharatnam-Berry) lenses. Such lenses are half-wave plates where the orientation of the fast (slow) axis follows a quadratic relation with the radial coordinate, and they present the same focal length but opposite sign for left and right circular polarizations. Therefore, they split an input collimated beam in a converging beam and a diverging beam with opposite circular polarizations. This coaxial polarization selectivity introduces a new degree of freedom in optical processing systems and makes it interesting for imaging and filtering applications that require polarization sensitivity. Here we profit from these properties to build an optical Fourier filter system with polarization sensitivity. A telescopic system is used to have access to two real Fourier transform planes, one for each circular polarization. A second symmetric optical system is used to recombine the two beams onto a single final image. As a result, polarization sensitive optical Fourier filtering can be applied, as demonstrated with simple bandpass filters.
本文提出了一种使用几何相位（Pancharatnam-Berry）透镜进行偏振图像处理的新型光学系统。这种透镜是半波片，快（慢）轴的方向与径向坐标呈二次关系，它们具有相同的焦距，但对于左旋和右旋圆偏振光具有相反的符号。因此，它们将输入的准直光束分裂成会聚光束和发散光束，其圆偏振光具有相反的方向。这种同轴偏振选择性为光学处理系统引入了一个新的自由度，使其在需要偏振灵敏度的成像和滤波应用中变得有趣。在这里，我们利用这些特性构建了一个具有偏振灵敏度的光学傅里叶滤波系统。使用望远镜系统来访问两个真实的傅里叶变换平面，每个平面用于一种圆偏振光。使用第二个对称的光学系统将两束光重新组合到单个最终图像上。结果，可以应用偏振敏感的光学傅里叶滤波，如用简单的带通滤波器所示。
