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: [email protected] > To: [email protected] > CC: [email protected] > > 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 <[email protected]>: > > 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
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