FFT and Optical Spectra

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?

Answer 1

[Peter Cook]

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.

[Sohel Rana]

Hi Paul,

Did you resolve the issue. I'm facing similar kind of problem. Could you please help me with that?