Hi,
I have been working on this code in matlab to create a color plot of contrast as a function of d2 and lambda. But I can't get it to work. I have tried to use pcolor and contourf. I am expecting the contrast to be on the order of 0 to 0.15, but I am getting 0 to -40. I have checked all of the equations and they are correct. Can anyone help me?
CODE
%Contrast(d2,lambda)
%indices for n2, refractive indices of SiO2
t = [1.4769372413793105 1.4761096551724138 1.4752820689655173 1.4745 1.4738828715365238 1.4732657430730478...
1.4726486146095716 1.4720314861460957 1.4714143576826195 1.4707972292191436 1.4701801007556674...
1.4695720257234728 1.4691057877813505 1.4686395498392282 1.468173311897106 1.4677070739549838...
1.4672408360128617 1.4667745980707394 1.4663849999999998 1.4660099999999998 1.465635 1.46526...
1.464885 1.46451 1.464155737704918 1.463827868852459 1.4635 1.463172131147541 1.462892...
1.4626253333333334 1.4623586666666666 1.462092 1.4618328 1.4615928 1.4613528 1.4611128 1.4608728...
1.4606328 1.4603928 1.4601528 1.4599485436893203 1.459754368932039 1.4595601941747574...
1.4593660194174758 1.4591718446601942 1.4589776699029127 1.4587682352941178 1.4585917647058824...
1.4583781651376146 1.4582222018348623 1.4580662385321101 1.4579102752293578 1.4577543119266054...
1.4575983486238533 1.457442385321101 1.4572864220183486 1.4571304587155964 1.456974495412844...
1.456818532110092 1.4566712000000002 1.4565512 1.4564312 1.4563034782608695 1.4561730434782607...
1.4560431524547803 1.455913953488372 1.4557847545219638 1.4556555555555555 1.4555263565891472...
1.4553971576227391 1.4552679586563309 1.4551387596899226 1.4550375 1.4549482142857144 1.4548589285714286...
1.4547696428571428 1.4546803571428573 1.4545910714285715 1.4545017857142857 1.4544125 1.4543232142857143];
%indices for n3, refractive indices of Si
s = [5.43578947368421-2.988473684210526i 5.656857142857141-3.0185714285714282i...
6.051857142857142-2.9898095238095244i 6.546714285714283-2.669428571428575i...
6.811-2.033090909090908i 6.736391304347825-1.3989130434782595i 6.469347826086958-0.9665217391304362i...
6.185-0.714i 5.943760000000001-0.5587600000000003i 5.740399999999998-0.4543999999999993i...
5.57-0.387i 5.425407407407407-0.33092592592592573i 5.296037037037037-0.2950740740740741i...
5.186785714285715-0.2605000000000002i 5.088964285714286-0.23771428571428582i...
5.0023793103448275-0.2098965517241379i 4.923500000000001-0.1955i 4.852161290322581-0.185i...
4.787322580645162-0.16932258064516126i 4.7289375-0.15337500000000004i 4.673757575757576-0.14512121212121204i...
4.623-0.13148484848484848i 4.575941176470589-0.13023529411764706i 4.5317428571428575-0.13305714285714287i...
4.491777777777778-0.12i 4.4543243243243245-0.10540540540540558i 4.420216216216216-0.09335135135135131i...
4.386578947368421-0.08226315789473686i 4.355307692307692-0.07802564102564102i 4.3253076923076925-0.07392307692307692i...
4.297487804878049-0.07282926829268294i 4.271634146341463-0.06746341463414635i...
4.245952380952381-0.0665714285714285i 4.222441860465116-0.06i 4.1999767441860465-0.056837209302325574i...
4.178688888888888-0.05326666666666664i 4.1585777777777775-0.043044444444444434i 4.137829787234042-0.04538297872340428i...
4.119744680851064-0.04723404255319147i 4.10175-0.044i 4.084428571428572-0.04057142857142841i...
4.0682-0.033800000000000066i 4.052588235294118-0.03623529411764699i 4.037607843137255-0.03254901960784312i...
4.0225660377358485-0.03301886792452832i 4.009222222222222-0.02944444444444445i...
3.9954444444444444-0.0273333333333333i 3.9825-0.03i 3.97-0.03i 3.9585087719298246-0.027578947368421054i...
3.9472586206896554-0.025655172413793104i 3.9366949152542374-0.025i 3.9262333333333337-0.024633333333333337i...
3.915639344262295-0.023606557377049187i 3.905793650793651-0.022i 3.8954761904761903-0.022i...
3.88646875-0.020218750000000008i 3.877569230769231-0.018630769230769232i 3.8683880597014926-0.017865671641791044i...
3.8594328358208956-0.017119402985074632i 3.851205882352941-0.016382352941176466i 3.8435217391304346-0.016i...
3.836225352112676-0.015929577464788725i 3.828478873239437-0.015225352112676047i 3.8208055555555553-0.014527777777777766i...
3.813378378378378-0.013837837837837827i 3.8066216216216215-0.013162162162162157i 3.8005-0.013i...
3.7945974025974025-0.013i 3.7887532467532465-0.013i 3.7830625-0.012562500000000006i 3.7773827160493827-0.011938271604938279i...
3.77120987654321-0.011320987654320993i 3.765951219512195-0.011i 3.7616829268292684-0.011i...
3.7565529411764707-0.010505882352941176i 3.751436781609195-0.01i 3.747413793103448-0.01i...
3.7429775280898876-0.009775280898876405i 3.737921348314607-0.009213483146067417i 3.7332747252747254-0.009i];
%d2 = 5e-9:5e-9:405e-9;
%lambda = 350:5:750; %wavelength of visible range
for i = 1:81;
d2 = i*5e-9;
for j = 1:81;
lambda = 345+5*j;
n0 = 1; %index of refraction of air
n1 = 2.6-1.3i; %index of refraction of graphene
d1 = 0.34e-9; %thickness of graphene
n2 = t(i);
n3 = s(i);
%define intensity
phi1 = 2*pi*n1*d1./(lambda*1e-9);
phi2 = 2*pi*n2*d2./(lambda*1e-9);
r1 = (n0-n1)./(n0+n1);
r2 = (n1-n2)./(n1+n2);
r3 = (n2-n3)./(n2+n3);
intensity = (abs((r1.*exp(i*(phi1+phi2))+r2.*exp(-i*(phi1-phi2))+r3.*exp(-i*(phi1+phi2))...
+r1.*r2.*r3.*exp(i*(phi1-phi2))).*(exp(i*(phi1+phi2))+r1.*r2.*exp(-i*(phi1-phi2))...
+r1.*r3.*exp(-i*(phi1+phi2))+r2.*r3.*exp(i*(phi1-phi2))).^-1)).^2;
%intensity with absence of graphene (n1=1)
phi1_n = 2*pi*d1./(lambda*1e-9);
phi2_n = 2*pi*n2*d2./(lambda*1e-9);
r1_n = (n0-1)./(n0+1);
r2_n = (1-n2)./(1+n2);
r3_n = r3;
intensity_n = (abs((r1_n.*exp(i*(phi1_n+phi2_n))+r2_n.*exp(-i*(phi1_n-phi2_n))...
+r3_n.*exp(-i*(phi1_n+phi2_n))+r1_n.*r2_n.*r3_n.*exp(i*(phi1_n-phi2_n))).*...
(exp(i*(phi1_n+phi2_n))+r1_n.*r2_n.*exp(-i*(phi1_n-phi2_n))+r1_n.*r3_n.*exp(-i*(phi1_n+phi2_n))...
+r2_n.*r3_n.*exp(i*(phi1_n-phi2_n))).^-1)).^2;
%contrast
contrast(i,j) = (intensity_n-intensity)./intensity_n;
end
end
A = 0:5:400;
B = 350:5:750;
pcolor(A,B,contrast)
xlabel('d2 (nm)')
ylabel('lambda (nm)')
colormap(jet)
colorbar
2 Jul, 2008 - 09:02 AM
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