For a highly focused beam, there is also a thin lens source that will inject a fully vectorial beam. The scalar approximation assumes that the fields in the direction of propagation are zero. By default, the Gaussian sources use a scalar beam approximation for the electric field which is valid as long as the waist beam diameter is much larger than the diffraction limit. When a broadband result at angled plane wave incidence is pursued with one simulation without using Bloch BCs, the BFAST source technique should be used, please read more on BFAST plane wave.Ī Gaussian source defines a beam of electromagnetic radiation propagating in a specific direction, with the amplitude defined by a Gaussian cross-section of a given width. Diffracting plane wave source can be used with PML in all directions. Periodic or Bloch boundary conditions should be used with Bloch/periodic type plane wave source. The plane wave source is actually the same object as the Gaussian source, with the only difference being the SOURCE SHAPE setting. It is also possible to inject a plane wave at an angle. In two-dimensional simulations, the plane wave source injects along a line, while in three-dimensional simulations the plane wave source injects along a plane. Plane wave sources are used to inject laterally-uniform electromagnetic energy from one side of the source region.
