Dear Allen, surely the best guide for defining the Lorentzian model for materials in MEEP is http://ab-initio.mit.edu/wiki/index.php/Meep_Tutorial/Material_dispersion where also a working example is presented.
I must apologize for the statement that you have to use a low-frequency Lorentzian oscillator; in fact, there is 'drude-susceptibility' in the current scheme interface of Meep. This function seems to be provided by libctl, which explains why I could not find it in the C++ sources nor it is present in the Python interface I use. Sorry that I cannot help with this, as I have no experience with the 'drude-susceptibility' function. Filip 2014-04-28 20:06 GMT+02:00, Allen Spencer <falcon_dai...@hotmail.com>: > Dear Filip, > Thank you very much for your reply! Suppose I want to use Drude model of > material:epsilon(omega)=eps_inf-sigma/(omega*(omega+i*gamma))with > eps_inf=12,sigma=0.3, gamma=1.6So how should I define this material in meep? > In MEEP reference I found lorentzian-susceptibility and > drude-susceptibility but I haven't get how should I define this material > using these functions. I am looking forward to your reply! > Regards,Allen > >> Date: Mon, 28 Apr 2014 19:12:11 +0200 >> Subject: Re: [Meep-discuss] Drude material in MEEP >> From: filip.domi...@gmail.com >> To: falcon_dai...@hotmail.com >> CC: meep-discuss@ab-initio.mit.edu >> >> Dear Allen, >> If I correctly understand your question, the Drude model can be >> approximated by the polarisation coming from a Lorentz oscillator with >> as extremely low resonance frequency. General approach is to select a >> realistic plasma frequency (for instance, omega_p := 2*pi*3.64e15 >> rad/s for aluminium), then to select some low enough oscillator >> frequency omega_0 (e.g. 1 rad/s) and finally to adjust the oscillator >> strength to be omega_p**2/omega_0**2 so that the actual plasma >> frequency is (almost) independent of the arbitrary value of omega_0. >> You may set the gamma value to some realistic one, e.g. gamma := 10e12 >> rad/s to introduce losses. >> >> At the moment, I am writing a text about how to correctly define >> conductor models for FDTD that are both realistic and numerically >> stable, as there are nontrivial points. I am going to share it when it >> is done. Some preliminary chaotic notes are at >> http://fzu.cz/~dominecf/misc/meep/index.html#drude. >> >> Regards, >> Filip >> >> 2014-04-28 18:12 GMT+02:00, Allen Spencer <falcon_dai...@hotmail.com>: >> > Dear MEEP users, >> > Dose any one know how to define a Drude material >> > (epsilon=eps_inf-sigma/omega*(omega+i*gamma)) but without Lorentz >> > oscillating term using polarizations in MEEP. Thanks in advance for >> > your >> > help! >> > Regards,Allen > _______________________________________________ meep-discuss mailing list meep-discuss@ab-initio.mit.edu http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
