Meta-Structured Phase Retarder

Quarter-wave plates – optical elements that can shift polarization states from linear to circular and vice versa – are quite versatile tools used in many different applications, from laser resonators to petrographic microscopes. In particular, diffractive waveplates are a variant of this type of element that is currently increasing in popularity. Diffractive waveplates use subwavelength periodic structures to produce the polarization shift, while maintaining high reflectance over a wide wavelength range. In this use case, we will demonstrate and analyze one such structure that has been optimized to work with a C0₂ laser beam.