We will now place a detector for optical analysis. Place a detector object as object #9 with the following parameters.

Ref Object: -1
Z position: 20
Material: Absorb
X Half Width: 25
Y Half Width: 6
# X Pixels: 400
# Y Pixels: 100
Data Type: 0 (incoherent irradiance)
Color: 0 (Gray scale for the detector viewer)

Open the detector viewer

Trace analysis rays to the detector with the "Use Polarization" option checked. The polarization option is used so that the energy lost due to partial reflections and bulk absorption is accounted for.

As discussed in the beginning of this article, the appearance of multiple elliptical beam at the detector is due to rays going through different number of total internal reflections.  



To see how the layout changes when changing the Outer R parameter, use the Slider Tool under Tools>Miscellaneous>Slider. Set the parameters for the slider as follows and press Animate

The layout shows how the bend radius changes

You can change the Outer R parameter and re-trace the detector to see the effect on the irradiance distribution. A simple ZPL macro can be written to trace the detector and save the result for each parameter value. The following movie with changing irradiance distribution in it was created by using such a macro.