On Sep 8, 2009, at 7:06 AM, 加祥 张 wrote:
Meep tutorial says that the units of power and electric field
in meep could be arbitrary which depend on the geometry, so I think
that the unit of electric field in meep could be V/a, "a" is the
lattice constant, Is it right? and the power intensity in meep
I'=1/2*n*|E'|^2, it has unit of (V/a)^2 (note that epsilon_0=1,
c=1). As we know, the electric field E in SI is V/m, so the
relationship between those is: E'=E* (a/m), is it right? so far, the
relationship between I' and I is: I=1/2* epsilon_0*c*n*|E|^2=1/2*
epsilon_0*c*n*|E'|^2* (a/m)^2=epsilon_0*c*(a/m)^2* I', and is it
right ? can anybody tell me about that? i want to obtain the real
power intensity (SI) according to the simulating results in meep
software.
The power intensity is in arbitrary units because the units of current
are arbitrary.
To set a unit, you have to normalize in some way. This is why you
normally compute a normalized (fractional) transmission as in the
tutorial. You can then multiply this by your input power to get the
absolute output power, if desired, e.g. if you have a waveguide bend
and the transmission is 50%, then if you input 2 Watts you will get 1
W out.
Steven
_______________________________________________
meep-discuss mailing list
[email protected]
http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
