Rigorous vector wave propagation for arbitrary flat media

Abstract

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 Maxwell's 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 ∼ 10 −16 for non-absorbing isotropic and anisotropic materials. For absorbing materials the precision is on the order of ∼ 10 −8 . The capabilities of the code are demonstrated by simulating a converging beam reflecting from a flat aluminium mirror at normal incidence.The precise characterization of optical systems is important for many applications, e.g. lithography, 1 microscopy 2 and astronomy. 3 Technology pushing the boundaries of the accuracy and sensitivity of optical systems, requires simulation tools that predict to a high accuracy the point spread function (PSF) of the systems. Polarization aberrationsThe monochromatic scalar aberrations of the wavefront, i.e. the phase and amplitude deviations from the ideal wavefront, were for a long time the only aberrations taken into account when simulating optical systems. These aberrations are caused by variations in the optical path length (OPL) and transmission for rays propagating through different parts of the optical system. These and chromatic aberrations have the the largest impact on image formation. As optical systems start to operate under more extreme numerical apertures and host more sensitive polarimeters, aberrations that affect the polarization state, which are much weaker than scalar aberrations, become relevant. We define polarization aberrations as the undesired deviations from the ideal system, a system which preserves the polarization state of light. Similar to scalar aberrations, polarization aberrations are caused by amplitude and phase effects. Diattenuation is the difference in transmission between two orthogonal polarization states. This can be due to different amplitude effects for the polarization states when reflecting off a surface. Retardance is the difference in OPL between two orthogonal polarization states, which is for example the result of propagation in anisotropic arXiv:1811.09777v1 [physics.optics]