White Paper: User-Defined Coatings And Polarization Ray Tracing

User-defined Coatings and Polarization Ray Tracing are important features, provided by LightTools, for modeling a wide variety of illumination systems. This paper describes the theory behind some common coating and polarization effects, and compares the theory with equivalent LightTools models for several example systems. LightTools models and analysis results are also described in several examples of real world systems.

The capability to specify multi-layer thin film coating performance characteristics as a surface optical property has been implemented in LightTools. This allows the user to specify the transmission and reflection characteristics of a coated surface in terms of ray trace parameters. The ray trace parameters available are wavelength, angle of incidence, and X,Y position on the surface. The transmittance and reflectance of the coating can be specified for the electric field vector components (s and p), or the average transmittance and reflectance of the electric field vector components.

LightTools has the capability to perform ray tracing with polarized, unpolarized, and partially polarized light. Polarizing elements and polarizationdependent optical coatings are also supported. There are three ways to specify the input polarization state of a ray: a geometrical representation in terms of a polarization ellipse, definition in terms of Jones vectors, or definition in terms of Stokes vectors.