Characterizing the polarization and cross-polarization of electromagnetic vortex pulses in the space-time and space-frequency domain

The dynamics of the degree of polarization and the degree of cross-polarization for electromagnetic pulsed vortex beams in dispersive media are explored both in the space-time and space-frequency domains. It is shown that the impacts, arising from the second-order dispersion coefficient and the temporal coherence length, on the variations of the temporal degree of polarization are distinctly different from those on the spectral degree of polarization. Besides, we also suggest a method to access the measurement of the orbital angular momentum of pulsed vortex beams through the mapping relationship between the distribution of the temporal degree of cross-polarization and the number of topological charge. (C) 2015 Optical Society of America