typically when folks are writing eps = x +/- iy, they're considering the dielectric as a function of frequency. Of course, as Meep is performing time-domain simulations, the dielectric / susceptibility instead need to be specified in terms of their possible time-domain dynamics, and then you need to choose simulations parameters such that you eventually reach a steady-state. This is especially true of saturable, multi-level atomic media, for which there is an additional "field," i.e. the inversion of the atomic media, which carries information about the dynamics of the system. Assuming you choose initial parameters which lead to steady-state behavior (for which one would likely just have to guess and check), you'll need to decide on an operating frequency, and then pick a set of parameters for the oscillation and decay rates of the media that yield the desired dielectric using, say, Eq. 20 of https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-23-5-6455&id=312584.
On Tue, Oct 20, 2020 at 3:47 PM Cícero Julião <juliaojun...@gmail.com> wrote: > Dear friends, > > I'm trying to implement PT symmetry in meep. One part of the material has > epsilon = x + i * y, the other part has epsilon = x - i * y (the imaginary > part has different signs for each part of the material). The problem is: > the fields blows up. In a previous email, a colleague on this list > suggested looking at saturable media. The way to put saturable media is > shown in this tutorial: > https://meep.readthedocs.io/en/latest/Python_Tutorials/Multilevel_Atomic_Susceptibility/ > . > > My problem now is: how to 'convert' the epsilon I hope to use in the > saturable media 'language', as shown in tutorial? If anyone can help, it > will be wonderful. > > Sorry if it's a stupid question, but I really need help. > > Thank you very much. > > > > -- > > Cícero Julião da Silva Junior > ____________________________________ > Instituto Federal de Alagoas - IFAL > Campus Murici > http://www.ifal.edu.br/ > _______________________________________________ > meep-discuss mailing list > meep-discuss@ab-initio.mit.edu > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
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