Abstract

The refractive indices of vanadium dioxide (VO2) abruptly change when its phase transition temperature of 68oC is reached, the point at which it goes from an insulating state to a metallic state. Modifications of complex-valued refractive indices in VO2 have been shown to produce optical phase shifts that are unequal for the s- and p-components of polarization, thereby causing a relative phase shift Δ between the two. Under certain conditions of Δ, a linearly polarized light can rotate its polarization 90 degrees or transforms between linear and circular. In this thesis, we will demonstrate all possibilities of using a VO2 thin film to change the polarized light states of reflected or transmitted light on the nanosecond and potentially shorter timescales. Possible applications for high-contrast optical modulation over a wide spectral range are discussed.