Hello all.
I am trying to reproduce the changes on a ~30 femtosecond laser pulse. I create and display this pulse in time just fine. Also, the fft of this pulse apperas fine on matlab (central frequency and width are very fine). But when I backtransform the transformed one using the ifft() function, the pulse is moved in time (posssibly due to phase change?? I don't know) and also the peak maxima are different.. What could be the cause of this? I am using ifft the wrong way?
The code I am using is this :
atto=1e-18;c = 299792458;femto=1e-15;lamda0=800e-9;f_0=c/lamda0;omega0=2*pi*c/lamda0;T=2*pi/omega0;a=2*log(2)/((36.32*femto)^2);Fs=3/atto; %samplying rate
t=-200*femto:1/Fs:200*femto;Efield=exp(-a.*(t-T).^2).*exp(1j.*omega0.*(t-T));nfft=2^nextpow2(length(Efield));Efieldfft=fft(Efield,nfft);f=(0:nfft-1)*Fs/nfft;omega=2*pi*f;figure(1)plot(t,Efield)xlabel('s [fs]')ylabel('Amplitude')figure(2)plot(omega,abs(Efieldfft))xlim([2e15 2.8e15])xlabel('omega [rad]')ylabel('Amplitude')figure(3)plot(f,abs(Efieldfft))xlim([3.3e14 4.1e14])xlabel('frequency [Hz]')ylabel('Power')test=ifft(Efieldfft,length(t));figure(4)plot(t,test)xlabel('s[fs]')ylabel('amplitude')
Test is the backtransformed function to time… Looking forward for your answers
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