Laser ray-tracing phenomenal model at far field

Wigner distribution function method includes diffractive effects into the conventional ray tracing model of laser beams. However, there are some difficulties when using this method in hydra-dynamics codes. Wigner distribution function method needs a large number of laser rays to describe laser energy distribution in phase space, which results in efficiency reduction in hydra-dynamic simulations. This paper proposes a phenomenal model which is based on Wigner distribution function. This model can describe the macroscopical intensity distribution of practical laser beams on positions at and off the focal spot. And the continuous phase plate (CPP) can also be described in this model.