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Drude, Lorentz, Johnson and Christy

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Dear Fellows,

I have a question which is not related with software but with some functions which we use in software.

I have to model optical antenna (gold on glass substrate). It is very common problem as you know in RF module. And also I have some metal tip above this structure.

Now I have question.


Have you ever use some other dielectric function of gold (or silver , whatever) except interpolation of vaules from Johnson and Christy?

Does any of you know something about these rules, when we use Drude model, when we use Lorentz expansion, when we use just vaules from Johnson and Christy etc.

Furthermore, does any of you compare results between case when glass substrate has constant dielec. function, and case when glass dielectric constant depends on wavelength?


Anyway, I am ecpecially interested in these rules about Drude, Lorentz, and Johnson and Christy.



Thank you every much on every response.






2 Replies Last Post 7 août 2012, 21:49 UTC−4

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Posted: 1 decade ago 7 août 2012, 21:00 UTC−4
Table data should be good if you don't go to nanomaterials (say, below 10 nm). I don't see a point using some models when the measured and verified data is available.

Of course it's all different with nanomaterials. There are no good enough models. So again it's better to use bulk data unless you can measure it yourself for your particular structures.
Table data should be good if you don't go to nanomaterials (say, below 10 nm). I don't see a point using some models when the measured and verified data is available. Of course it's all different with nanomaterials. There are no good enough models. So again it's better to use bulk data unless you can measure it yourself for your particular structures.

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Posted: 1 decade ago 7 août 2012, 21:49 UTC−4
Hello Alexander,

Thank you very much for your answer.


This is my module:

gold dipole antenna (length 30nm, width 20nm, height 25nm)

Tip (height around 600nm)

Indium tin oxide thickness 30nm.


So you think for such structure there is not necessary to use Drude or Lorentz?


Thank you for helping.
Hello Alexander, Thank you very much for your answer. This is my module: gold dipole antenna (length 30nm, width 20nm, height 25nm) Tip (height around 600nm) Indium tin oxide thickness 30nm. So you think for such structure there is not necessary to use Drude or Lorentz? Thank you for helping.

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