Free-space propagation#
Free-space calculations describe a beam in a bulk medium. Choose a radial grid when cylindrical symmetry is appropriate, a Cartesian grid for two transverse coordinates, or a line grid for a field uniform in one direction. Read the spatial overview first if this choice is unfamiliar. The radial filament lesson and Cartesian crossing beams introduce the main workflows. The focused examples extend them to focusing, diffraction and analysis. The capillary coupling tutorial prepares a beam in a gas gap and couples its entrance field into a capillary.