Hello meep users,
I tried to calculate the transmittance and reflectance of glass
(eps=2.25). However, the result was strange; the resulting transmittance
and reflectance were fluctuated according to the frequency as the figure
in the link below.
https://drive.google.com/open?id=16aHzipAuuyIyyuambuQU2J_5fcwnpSSF
So, I would be grateful if someone would point out my mistakes in my
script or some misunderstandings.
The simulation space has PMLs at the both Y+ and Y- sides, and two
flux-regions: "trans" and "refl" are attached on these PMLs (Y+ and Y-,
respectively). Note that there is periodic boundary conditions. To
subtract the direct incident to the "refl" flux-region, I did two
simulations with and without the glass. The illustration of the
configuration is available in the following URL.
https://drive.google.com/open?id=1c5oqaMfG9UpIIzhrCRQ7nZVhxRNiIQU-
As for the scheme script, please see the following.
;-----------------------------------------------------------------------------
; test.scm
;-----------------------------------------------------------------------------(define-param
obj? 1)
(set-param! resolution 30)
(define-param sx 4)
(define-param sy 8)
(define-param dpml 1)
(set! geometry-lattice (make lattice (size sx (+ sy (* 2 dpml)) no-size)))
(set! k-point (vector3 0 0 0))
(set! pml-layers (list
(make pml (thickness dpml)(direction Y)(side Low))
(make pml (thickness dpml)(direction Y)(side High))))
(if (= obj? 1)
(set! geometry (list
(make block (center 0 1) (size sx 2)
(material (make dielectric (epsilon 2.25)))))))
(define-param fcen 1.0)
(define-param df 0.6)
(define-param fnpont 101)
(define-param src-cmpt Ex)
(set! sources (list (make source
(src (make gaussian-src (frequency fcen) (fwidth df)))
(center 0 -2)
(size sx 0 0)
(component src-cmpt))))
(define trans
(add-flux fcen df fnpont
(make flux-region (center 0 (* 0.5 sy)) (size sx 0))))
(define refl
(add-flux fcen df fnpont
(make flux-region (center 0 (* 0 -0.5 sy)) (size sx 0) (weight -1))))
(if (= obj? 1) (load-minus-flux "refl-flux" refl))
(run-until 200)
(if (= obj? 0)(save-flux "refl-flux" refl))
(display-fluxes trans refl)
;-----------------------------------------------------------------------------
;-----------------------------------------------------------------------------
To run the code, please hit the following:
meep obj?=0 test.scm
meep obj?=1 test.scm | tee a.out
grep flux1: a.out>a.csv
To plot the result please use the following matlab script:
%------------------------------------------------------------------------------
%------------------------------------------------------------------------------
filename = 'a.csv'; fid = fopen(filename);
data = [];
while ~feof(fid)
tline = fgetl(fid);
C = strsplit(tline);
add_tmp = [str2double(C(2)); str2double(C(3)); str2double(C(4))]';
data = [data; add_tmp];
end
fclose all;
f = data(:,1);
trans = data(:,2)./(data(:,2)+data(:,3));
ref = data(:,3)./(data(:,2)+data(:,3));
plot(f, trans, 'r', f, ref, 'b');
legend('Trans.', 'Refl.'); xlabel('frequency');
set( gca,'FontSize',16 );
xlim([0.7, 1.3]), ylim([0 1]);
%-------------------------------------------------------------------------------
%------------------------------------------------------------------------------
Best,
Hirokazu Ishida
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