  Several emerging microscopy imaging methods rely on complex interactions
between the incident light and the sample. These include interferometry,
spectroscopy, and nonlinear optics. Reconstructing a sample from the measured
scattered field relies on fast and accurate optical models. Fast approaches
like ray tracing and the Born approximation have limitations that are limited
when working with high numerical apertures. This paper presents sCWatter, an
open-source tool that utilizes coupled wave theory (CWT) to simulate and
visualize the 3D electric field scattered by complex samples. The sample
refractive index is specified on a volumetric grid, while the incident field is
provided as a 2D image orthogonal to the optical path. We introduce connection
equations between layers that significantly reduce the dimensionality of the CW
linear system, enabling efficient parallel processing on consumer hardware.
Further optimizations using Intel MKL and CUDA significantly accelerate both
field simulation and visualization.
