Analytical vectorial structure of Gaussian beams carrying mixed screw–edge dislocations in the far field

Abstract

Based on the vectorial angular spectrum representation and stationary phase method, the explicit expressions for the TE and TM terms and energy flux distributions of Gaussian beams carrying mixed screw–edge dislocations in the far field beyond the paraxial approximation are derived and used to study their far-field properties. It is shown that there are phase singularities of electric or magnetic component and dark spots of energy flux distributions. By varying the controlling parameters such as the dislocation slope, off-axis distance, waist width, the motion and pair-annihilation of phase singularities and variations of energy flux distributions may appear. Under certain conditions, the phase singularities and energy flux distributions are symmetric about the origin. A comparison with the previous work is also made.