Real-time monitoring of white light source characteristics in a correlation Fourier spectrometer

摘要

The high temporal resolution and accuracy of spectrum restoration achieved with a correlation Fourier spectrometer substantially depend on the precise knowledge of the optical characteristics of the used operating white light source. However, the beforehand calibration of this source does not guarantee avoiding of errors due to random disturbances during spectrometer's operation. In the present work we solved two tasks. We analyzed the noise sources in a three-channel Fourier spectrometer with simultaneous recording of interferograms for the etalon light source, for the operating source and for the investigated sample using Monte-Carlo simulations. As a second task we made a prototype of a correlation Fourier spectrometer and simulated the real-time tracking of changes in autocorrelation functions of different semiconductor light sources (LD, LED and high-power LED) using the measured interferograms. We proposed an analogous feedback system to perform a current correction of the autocorrelation of the operating light source following the changes in the autocorrelation function of the etalon source.