For ZEMAX to recognize the newly created ideal coating, you must choose your new catalog from the “Coating File” field in the System General dialog.



To apply the coating the front face of the Rectangular Volume, open the Object Properties dialog for Object 2, and select the “Coating/Scattering” tab.  The first available menu under this tab is the “Coating/Scatter Group.”  Each object, depending upon its type, has different coating/scatter groups.  For the Rectangular Volume Object, there are three groups:  0, Side Faces; 1, Front Face; and 2, Back Face.



Because of this, different coatings and scattering profiles may be applied to different faces of the object.  For the current example, select the “Coating/Scatter Group” as 1, Front Face. 

By default, no coating is applied to any surface.  For the front face of the rectangular volume, the newly created ideal coating may be applied via the “Coating” pull-down menu just below the Coating/Scatter Group selection.



Once the appropriate coating is selected, press “OK” to accept the changes and exit the Object Properties dialog.  To verify that the coating is applied and is working properly, we can run a Monte Carlo Ray Trace with Use Polarization checked.



As expected, the total power of the ray reaching the detector has been reduced, and is exactly 60% of the initial power of the ray: