We now have the straight (refracted) path of the beam splitter modeled. You can specify any amount of transmission by defining additional ideal coatings in the coating file. You can also create a non-ideal coating either by specifying coating layer thicknesses and material type or the transmission properties of the coating as a function of wavelength and incident angle. For more detailed information about how to define coatings in ZEMAX, please refer to chapter 20, section “defining coatings in ZEMAX” of our latest manual. 

The effect of thin-film coating can only be accounted for when considering the polarization effects in the calculation or analysis, even if the coating is ideal. The total transmission at the image plane can be evaluated by any polarization-enabled analyses/calculations in ZEMAX.  We will use the Polarization Ray Trace to calculate the total chief-ray transmission at the image plane.

Open the polarization ray trace (Analysis > Polarization >Polarization Ray Trace)

Specify the following settings.

The total transmission is reported at the bottom of the window.

The Polarization Ray Trace is accounting for all loss mechanisms: AR-coated N-BK7 surfaces, 50/50 splitting and N-BK7 bulk absorption at the whatever wavelength the ray is traced at, and at whatever angle it makes to the surfaces.