A Comparison of Paraxial and Extended Paraxial Approach in Laser Propagation and Second Harmonic Generation

The propagation of laser beam in the plasma has been investigated for two cases, first with imposing the restriction of paraxial approximation on the beam profile, and second, relaxing the restriction on the profile up to a certain extent. The beam width parameter of the propagating laser beam has been compared for both the cases. Since the off-paraxial part of the beam affects background densities, consequently it will also influence the 2nd harmonic generation. Therefore, comparison of results has been done on the generated second harmonic, in the light of these two cases. A notable change is found in the magnitude of second harmonic yield in modified-paraxial case as compared to the paraxial case.