'Pass_P' coating fail for the modeling of a wire grid polarizer, how to model it correctly?

  • 30 August 2019
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I'm using coating 'Pass_P' to model a wire grid polarizer, which is made by fabricated narrow metal stripes on a glass substrate. The polarizer should reflect s-polarized light, while transmit p-polarized light. But the coating cannot handle it correctly, when I setup my system,  why the normal incident S-polarized light pass the surface with 'Pass_P‘ coating. 

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The term 's-polarized light' and 'p-polarized light' in above question is different from the one being defined in OpticStudio. In OpticStudio, vector S and vector P is the projection of E field, and the direction depends on k vector(ray propagation vector) and surface normal. When ray propagate normal to surface, the distinction between S and P polarization become ambiguous. See this forum post for more information.

In industry, people use the terms S and P polarization but they want rays being operated in X and Y direction.

In your case, the structure looks like the picture shown below.

You would like to simulate a polarizer that can reflect X polarization and let Y polarization transmit. However, the definition of S and P changes from ray to ray.

If a ray come from X direction with non-zero radial angle, the S polarization will be defined in Y direction.

And if the ray come from Y direction, the S polarization will instead be defined in X direction. This is obviously not the behavior of a polarizer.

So you cannot make the polarizer using the coating 'Pass_P'.  The coating is supposed to be used by elements like Polarizing beam spltters, you can see the light is supposed to be incident on a surface obliquely. 

For correctly setup the wire polarizer in OpticStudio Non-sequential mode, you should use the obejct 'Dural BEF surface' . The surface is an idealized surface that can reflect and transmit rays with variable amplitude depending upon the polarization state of the ray.The transmission and reflection intensity coefficients are defined as parameters 3-6, and are different for X and Y polarized light, where the X and Y directions are defined in the surface coordinate system.