On Aug 28, 2009, at 9:32 PM, 刘荣鹃 wrote:
Hi, meep users
I want to use meep to simulate nanostructure in gold film. I found
the defined
dispersive material parameters by some users pasted in the mail
archives are
different from that in the example material-dispersion.ctl. The
parameters
defined by meep user contain "delta-epsilon". However, it is
"sigma" in
material-dispersion.ctl. Does this difference come from the version
difference.
Yes, it was just a version difference. The two are equivalent.
what's the form of epsilon for dispersion material in old version
and current
version, respectively. Furthermore, who can tell me how to determine
the
parameters, omega, gamma,and sigma for gold in meep version 1.0.3 ?
The best parameters really depend on the frequency bandwidth you are
interested in. Ideally, you should fit the experimental data with a
permittivity parameterized as in Meep in your bandwidth of interest to
find the best parameters.
part and imaginary part. who can tell me how to fit the real part
and imaginary
part at the same time to get a set of A,B1,C1,D1,B2,C2,D2, namely,
(epsilon ),
(omega ), (gamma ),(sigma ) ? or the better method to get the
values of (
epsilon ), (omega ), (gamma ),(sigma ) for gold? or directly
tell me the
typical values of (epsilon ), (omega ), (gamma ),(sigma ) for
gold used in
meep version 1.0.3 ? thank you in advance!
It's a nonlinear fitting problem that you could set up in various
ways. For example, you could do a least-square fit where you minimize
the integral of the square of the absolute value of the error in the
complex permittivity over your desired bandwidth.
Steven
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