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Date 08/09/2010
Script S4_2_11.m
Download Script S4_2_11.m
%==============================================
%Fabry-Perot 4
%==============================================
%
%the sodium line 0.58900 microns
lambda=0.58900;
%the thickness t in microns
t=2.0e+003;
%angles on incidence between 0° and 1.35°
%in degrees
tetag=eps:0.001:1.35
%and in radians
teta=tetag*(pi/180);
%reflectivity, refractivity and their squares
%e i loro quadrati
ro=0.60;
tau=1-ro;
roq=ro^2;
tauq=tau^2;
%values of k and of fi
k=2*pi/(lambda);
fi=(k*2*t)*cos(teta);
%
%==============================================
%orders m1MAX and m2MAX
m1MAX=floor(k*t/pi)
m2MAX=m1MAX-1
%
%preliminary calculi
num3=tauq;
dena=1+roq;
%==============================================
%Calculus of Ir
%==============================================
denb1=2*(ro.*cos(fi));
denb11=dena-denb1;
Ir=num3./denb11
%
%==============================================
%for the first maximum
%
%only a part of the array of Ir is used
%to find values and positions for the maximum and minimum
Ir1p=Ir(201:601);
teta1=tetag(201:601);
[Ir1max,p1max]=max(Ir1p)
ang1max=teta1(p1max)
Ir11p=Ir(601:1001);
teta11=tetag(601:1001);
[Ir1min,p1min]=min(Ir11p)
ang1min=teta11(p1min)
%countercheck (see previous two problems)
fi1max=m1MAX*2*pi;
Ir1maxprova=num3/(dena-2*ro*cos(fi1max))
%==============================================
%for the second maximum
%only a part of the array of Ir is used
%to find values and positions for the maximum and minimum
Ir2p=Ir(1001:1201);
teta2=tetag(1001:1201);
[Ir2max,p2max]=max(Ir2p)
ang2max=teta2(p2max)
%countercheck (see previous two problems)
fi2max=m2MAX*2*pi;
Ir2maxprova=num3/(dena-2*ro*cos(fi2max))
%==============================================
%
%plot of the first two fringes
plot(tetag,Ir,'r-')
axis([0 1.35 0 1])
title('Ir of the first two fringes when tetag varies from 0° to 1.35°')
grid on
%==============================================
%
%angles to the right of a maximum
%corresponding to Ir = 0.5
%the array of Ir is observed finding the values
%0.5 in the position 498 for the first maximum
%hence
d1d=tetag(498)
%and in the position 1103 for the second maximum
%hence
d2d=tetag(1103)
%==============================================
%
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