Use the Thin Dielectric Film subnode to model the interaction of rays with walls or material discontinuities that are coated with thin, transparent dielectric layers. The presence of these layers modifies the Fresnel coefficients used to compute the intensity or power of the reflected and refracted rays. The films must be very thin relative to the coherence length of the radiation and are usually comparable to or smaller than the wavelength. The subnode is available from the context menu (right-click the Material Discontinuity or Wall parent node) or from the Physics toolbar, Attributes menu.

The Thin Dielectric Film subnode is applied to all boundaries in the selection of the Wall or Material Discontinuity parent node. The effects of the Thin Dielectric Film subnodes are applied when computing the coefficients of reflection and transmission, which are necessary for the reinitialization of Stokes parameters during reflection and refraction if the intensity is solved for in the model.

Enter a Film refractive index n (dimensionless). The default value is 1. Then enter a Film thickness t (SI unit: m). The default is 1 μm.

If Add layers to surface, repeating is selected from the Thin dielectric films on boundary list in the Coatings section in the settings window for the parent node, this section is used to determine which layers are part of the repeating unit cell of a periodic multilayer film. If the Repeat layer in multilayer films check box is selected, the layer is repeated a number of times equal to the Number of repeating unit cells specified in the parent node settings window. If the check box is cleared, the layer will appear only once in multilayer films.