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aphirst
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Homework Statement
I'm implementing the transfer matrix method (manually) for an EM wave through a 1D layered structure. Basically I'm just considering a plane wave in the positive-x direction, conserving E and H across each material interface, and constructing interface matrices, the appropriate matrix product of which allows you to work out forward/reverse coefficients in each region, and the reflectivity/transmittivity.
I have it set up such that I just make a big list of (complex) refractive indices, and the widths of each sublayer (or the positions of each interface); also specifying the angle of incidence (in the xz plane), and the polarisation (TE or TM, i.e. either E or H respectively entirely in the y-direction).
Whenever the refractive index on the far LHS (i.e. the material that extends to [itex]-\infty[/itex]) is equal to that on the far RHS (i.e. extending to [itex]+\infty[/itex]), reflectivity and transmittivity both work perfectly.
However when they differ, for instance in the case with only one interface; reflectivity behaves perfectly, while transmittivity is no longer bounded under 1.
Homework Equations
E-mail to my supervisor, in which I walk through the cases that do and don't work. Includes plots.
https://dl.dropbox.com/u/3219541/Project/email.pdf [Broken], or the attached email.pdf
A transcript of my working for this method, including some explicit calculations to demonstrate the fact that R behaves, while T does not.
https://dl.dropbox.com/u/3219541/Project/calculations.pdf [Broken], or the attached calculations.pdf
The Attempt at a Solution
I went to see him to discuss the problem yesterday: he told me it was to do with that RHS/LHS difference (rather than an artefact of only performing the method for a single interface, which is what I had thought). He then said something about phase velocities, and about having to scale something according to the ratio of permittivities (or, complex refractive index squared), but wasn't massively clear where that was supposed to come up in the maths. I've read over the relevant sections of some EM textbooks, but I can't see how that's supposed to change what I've worked out.If any of you have the time to read over what I've done, and (if I'm fortunate) point me in the right direction, I'd really appreciate it.
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