Analysis and Control of Elliptically Polarized States of Light

Abstract

The most commonly referred states of polarization are linear and circular. However, both linear and circular polarizations are special cases of the generalized elliptical polarization state. This dissertation investigates three areas relating to elliptical po- larization. The first area of investigation is the study of optical components where the eigenpolarizations are neither linear nor circular; rather they are arbitrary ellip- tical polarization states. Designs of elliptically polarizing beam splitter cubes and elliptical retarders are presented. The components are fabricated utilizing multiple layers of liquid crystal polymer and characterized using Mueller matrix polarime- try. The second area of investigation is the reduction of polarization aberrations in common polarizing components by elimination of unwanted elliptical polarization states. The sources of polarization aberration include non-normal angle of incidence transmission through interference filters, reflection from metals, and total internal reflection. The correction can be achieved using different layers of birefringent coat- ing such as A-plate and C-plate liquid crystal polymers. Both diattenuation and retardance can be reduced across large spectral and angular bandwidths. The fi- nal area of investigation is the observation of elliptical polarization in the natural world. There are few sources of circular and elliptical polarization in nature, namely the reflections from beetle exoskeletons and metals with complex refractive index. However, total internal reflection at the water and air interface can lead to elliptical polarization as well. Static and dynamic scenes, under both laboratory and natu- ral illumination, are investigated using a polarization sensitive camera, all showing elliptical polarization of varying degrees of ellipticity. The three presented areas of investigation demonstrate the importance of elliptical polarization state of light and further our understanding of polarization optical design and imaging.