Re: [Camfr-users] Defining the angle of dependence.

[Peter B. <Pet...@ug...>]

The reason is that the code in set_theta actually sets the transverse part of 
the wavevector, which is dependent on lambda:

void Planar::set_theta(Complex theta_radians)
{  
  kt = (2*pi / global.lambda * core->n()) * sin(theta_radians);
}

So, you should always set the wavelength first before defining the angle.

I will update the documentation to reflect this.

Thanks for spotting this!

Peter

On Tuesday 26 August 2008 18:37:13 vra...@di... wrote:
> Hi everybody,
>
> we have a question on setting the angle of dependence. The code below is
> written to show the differences between setting the angle of dependence
> before and in the loop over wavelength. Why are the results different?
>
> Thank you for the answer!
>
> Vratislav
>
> #################################################
> # CAMFR test, 28. 8. 2008
> # Aim: to test CAMFR in setting angle properly
> #################################################
>
> from camfr import *
>
> # Define constants.
> theta = 80.
> angle = theta * pi / 180.
> set_lambda(1.)
> set_polarisation(TE)
>
> # Define structure.
> air_m = Material(1.0)
> layer_m = Material(3.4)
>
> Air = Planar(air_m)
> Layer = Planar(layer_m)
>
> Structure = Stack(Air(0) + Layer(1.) + Air(0))
>
> # Calculation - frequency dependence (with or without set_theta).
>
> Result = []
> for lambdaa in arange(0.1,4.,0.01):
>     set_lambda(lambdaa)
>     Structure.inc().set_theta(angle)
>     Structure.calc()
>     T = abs(Structure.T12(0,0))**2
>     Result.append((lambdaa,T))
>
> Structure.inc().set_theta(angle)
> for lambdaa in arange(0.1,4.,0.01):
>     set_lambda(lambdaa)
>     Structure.calc()
>     T = abs(Structure.T12(0,0))**2
>     Result.append((lambdaa,T))
>
> plot_vector(Result)

-- 
------------------------------------------------
Peter Bienstman
Ghent University, Dept. of Information Technology
Sint-Pietersnieuwstraat 41, B-9000 Gent, Belgium
tel: +32 9 264 34 46, fax: +32 9 264 35 93
WWW: http://photonics.intec.UGent.be
email: Peter.Bienstman@UGent.be
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