that may be desirable for different applications examples include low blue light absorption where color gamut and balance is important or low stress optic coefficient for high light intensity applications or higher index of refraction for smaller angular spread in the glass allowing smaller components where compact design is important secondly because tilted color separation coatings such as those used in color prisms are sensitive to angle a fully telecentric beam was used for these experiments this beam provides a full u0192 2 cone at all points on the imager thereby ensuring that all allowable rays of light in an u0192 2 beam are represented at all image locations in our tests the system has been designed for maximum flexibility for example to allow easy changes of illumination u0192 the pbs 30 in fig1 a and 1 b is illuminated with light polarized into and out of the page vertically so it is nominally an s polarized beam with respect to the pbs the vertical direction will be referred to in the future as the y direction and the direction of light propagation will be referred to as the z direction the color prism 36 depicted is a so called philips prism however the detailed results are expected to be independent of the precise color prism configuration the y polarized light incident on the pbs from the lamp 12 is reflected by the pbs into the color prism the color prism is shown with its reflecting planes for red and blue light rotated about an axis parallel to that about which the pbs is rotated parallel to the y axis the configuration shown will be referred to as an u201c s oriented u201d color prism the other case to be considered is that where the color prism.