Propagation-induced changes in the instantaneous polarization state, phase, and carrier–envelope phase of few-cycle pulsed beams

Abstract

We describe the temporal evolution of the electric field of few-cycle optical pulses with arbitrary, time-varying polarization states by means of the instantaneous polarization ellipse and phase, whose physical meanings for few-cycle pulses are clarified. A physically meaningful definition of carrier–envelope phase (CEP) for arbitrarily polarized pulses is introduced. This description is used to study the changes in the temporal evolution of the electric field of a few-cycle pulsed beam. Propagation is found to result in significant changes in the polarization state, phase, and CEP. Approximate analytical formulas for these effects are provided.