  Precise modelling of the (off-axis) point spread function (PSF) to identify
geometrical and polarization aberrations is important for many optical systems.
In order to characterise the PSF of the system in all Stokes parameters, an
end-to-end simulation of the system has to be performed in which Maxwells
equations are rigorously solved. We present the first results of a python code
that we are developing to perform multiscale end-to-end wave propagation
simulations that include all relevant physics. Currently we can handle
plane-parallel near- and far-field vector diffraction effects of propagating
waves in homogeneous isotropic and anisotropic materials, refraction and
reflection of flat parallel surfaces, interference effects in thin films and
unpolarized light. We show that the code has a numerical precision on the order
of 1E-16 for non-absorbing isotropic and anisotropic materials. For absorbing
materials the precision is on the order of 1E-8. The capabilities of the code
are demonstrated by simulating a converging beam reflecting from a flat
aluminium mirror at normal incidence.
