I have a pretty good understanding that when polarized light is incident on a surface it will change handedness (Right handed polarization, to left handed polarization for example) and remains will remain circular if it is incident at an angle less than the Brewster angle, otherwise it will retain its handedness but become elliptically polarized. But what happens to the transmitted wave? How does it's handedness change? Can it ever remain circular? What happens at normal incidence?