019 MATLAB Fourier transformation

Fourier transformation

% Fourier transformation

 m = input('중심파장을 입력하시오.(nano)');
 sigma = input('분산의 크기를 입력하시오.(nano)');
 lamdamax = 400*1e-9;
 lamdamin = 1200*1e-9;
 lamda = linspace(lamdamin, lamdamax, 10000);
 Glamda = (1./(sigma.*(2.^(-1/2)))).*exp(-(lamda-m).^2./(2.*sigma.^2));

 subplot(3,1,1);
 plot(lamda,Glamda); Xlabel('lamda (m)'); Ylabel('amplitude');

 kmin = (2*pi)/lamdamax;
 kmax = (2*pi)/lamdamin;
 k = linspace(kmin,kmax,10000);
 mk = (2*pi)/m;
 sigmak = mk - ((2*pi)/(sigma+m));
 Gk = (1./(sigmak.*(2.^(-1/2)))).*exp(-(k-mk).^2./(2.*sigmak.^2));

 subplot(3,1,2);
 plot(k,Gk); Xlabel('k(1/m)'); Ylabel('amplitude');
 x = linspace(0,200,2000);
 fxx=linspace(0,0,2000);
 for p=1:10000
     fx = (1/(2*pi)).*Gk(p).*exp(-sqrt(-1).*k(p).*x).*((kmax-kmin)/10000);
     fxx=fxx+fx;
 end
 subplot(3,1,3)
 plot(x,fxx); ; Xlabel('t(time(s))'); Ylabel('amplitude');