MATLAB Answers

FFT and Optical Spectra

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Paul Clarkson
Paul Clarkson on 18 Oct 2017
Commented: Sohel Rana on 15 Jan 2021
I have saved optical spectra (Intensity vs wavelength) as text files. How do I load these text files into matlab, invert the wavelength into wavenumber, interpolate so that the data points are evenly spaced and then FFT the frequency domain spectrum?

Answers (1)

Peter Cook
Peter Cook on 18 Oct 2017
If you're looking for a simple import and speed isn't a concern you should try:
uiimport
A speedier load than this can be achieved using low-level IO functions.
Depending on your field, converting wavelength to wavenumber is achieved using either
waveNumber = 1./waveLength
%or
waveNumber = 2*pi./waveLength
The interpolation you are looking for can be achieved using either
interp1
%or
interp2
depending on the dimensions of your data, or using the
resample function if you want some antialiasing.
The FFT is done with the aptly named
fft
function.
I am not exactly sure what you're doing, but I think you could probably skip most of these steps and just fft the intensity vs wavelength data to achieve the same goal.
  1 Comment
Sohel Rana
Sohel Rana on 15 Jan 2021
Hi Paul,
Did you resolve the issue. I'm facing similar kind of problem. Could you please help me with that?

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