The electric field at the output of an optical system is in general affected by both aberrations and diffraction. Many simulation techniques treat the two phenomena separately, using a geometrical propagator to calculate the effects of aberrations and a wave-optical propagator to simulate the effects of diffraction. We present a ray-based simulation method that accounts for the effects of both aberrations and diffraction within a single framework. The method is based on the Huygens–Fresnel principle, is entirely performed using Monte Carlo ray tracing, and, in contrast to our previously published work, is able to calculate the full electromagnetic field. The method can simulate the effects of multiple diffraction in systems with a high numerical aperture.@en