Influence of different pulse width on electron emission characteristics driven by circularly polarized intense laser

The influence of pulse width on relativistic motion and full spatial characteristics of radiation generated from electron oscillations driven by circularly polarized intense femtosecond laser pulses have been investigated theoretically and numerically using a single electron model. The electron trajectories show asymmetric spiral patterns for few-cycle laser pulse which do not resemble with twofold symmetric spiral patterns in the multi-cycle laser pulse. It is discovered that the patterns of the full spatial distribution of electron emission are of the shape resembling a flower of calla for few-cycle laser pulse and the radiated power per unit solid angle show a horn like shape directed toward the direction of the laser pulses propagation with a narrower divergence for multi-cycle laser pulse.