Method for precise measurement of optical characteristics of light sources with correlation Fourier spectrometer

Abstract

Observation of ultra-fast relaxation processes with time-constants below 1 ps in a wide spectral range can be made using a low-coherent light source, which is equivalent to a very short pulse in the non-linear correlation spectroscopy. The same approach can be used for very accurate and practically in real time determination of spectra of coherent and non-coherent light sources by recording and processing of their correlation functions. To check the proposed approach, we made a prototype of a correlation Fourier spectrometer based on a Michaelson interferometer and we developed a method for processing of the recorded interferograms which had been proved by a Monte-Carlo simulation. Different semiconductor light sources (LD, LED and high-power LED) were tested. The good quality of the obtained spectra was confirmed by comparison with OSA measurements (resolution 0.28 nm). The time required for data recording and spectrum restoration is within few seconds. This permits current tuning of the investigated sources, which extends their possible applications in spectroscopy, optical communications, computer technologies, etc.