Why do I lose power reflecting off mirrors with nsc tracing and the "use polarization" flag?

  • 28 April 2024
  • 4 replies

I feel like I should know the answer, but for the life of me I cannot make sense of it. 

If I create a very simple NSC model consisting of a 1 Watt source reflecting at normal incidence off a flat mirror and then absorbed a by a detector also at normal incidence, the power absorbed by the detector will vary whether I have “Use Polarization” checked or not.  With use polarization, the power is ~0.946 Watts, without it is 1.0 Watts.

What gives?

I am running an older version of Optics Studio but can upgrade (22.1.2).


Best answer by David 29 April 2024, 02:25

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4 replies

Userlevel 6
Badge +4

Optic Studio models MIRROR as a thin layer of metal which does not reflect 100%. For 100% reflectance you can use an IDEAL coating. 

Thanks David.  Is this a change from older versions?  I don’t remember noticing this in the past.

Userlevel 6
Badge +4

It’s been this way as long as I can remember. It’s often been a source of confusion. 

Userlevel 7
Badge +3

Just to add a bit more detail to David’s answer, here’s what the 2002 Zemax User’s Guide says: