Figure 3. Simulation results showing the generation and amplification of a new OAM modes.

The new mode with grow from a seed with and a linearly polarized pump with a Gaussian profile in the x direction, and with an OAM in the y direction. z=2 mm (a) and z=6.22 mm (b). The initial set-up is illustrated in Fig. 1b. Projections in the (x,z-ct) and (y,z-ct) planes show intensity profile slices at the mid-plane of the OAM mode (blue–green–red colours). Projections in the (x,y) plane (blue–white–red) show the normalized vector potential (a₀) field envelope of the new OAM mode at the longitudinal slice where the laser intensity is maximum. The envelope of the 3D laser intensity is also shown for z>6.25 mm in blue–green–red colours, and normalized vector potential isosurfaces for z<6.25 mm in blue and red.