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victorliu / S4

Stanford Stratified Structure Solver - Electromagnetic simulator for layered periodic structures
http://www.stanford.edu/group/fan/S4/
GNU General Public License v2.0
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Layer Thicknesses #96

Open anthmanni opened 3 years ago

anthmanni commented 3 years ago

Quick question. Are the layer thicknesses defined in terms of the lattice constant? Or are they absolute?

e.g. if my pitch is 0.68µm and I enter a layer thickness of 0.2, is it 0.2µm or 0.2*0.68 = 0.136µm?

Thanks!

charey6 commented 3 years ago

In my understanding, all the lengths in S4 are relative length, as here. That is to say you can define any unit you want, but the unit has to be consistent.

If you set the lattice as (0, 0.68), and you enter thickness = 0.2, then it means 0.2um. However, if you set lattice as (0, 1), and the actual lattice size in your mind is 0.68um, then a thickness of 0.2 means 0.2*0.68um, since your absolute lattice size is 0.68um while you set it to 1. In this case, the unit is 0.68um.

Just be consistant and maybe thinking all the numbers in unit of um is easier.

anthmanni commented 3 years ago

@charey6 that makes sense, thank you for the reply!