Experimental Research on Dispersed Fringe Sensing Based on Fourier Transform

For optical interference, to realize the co-phasing effect is important, especially rigorous for broadband white light interference. In order to realize stable white light interference, we need to make real-time detection and compensation control for the piston error. Through theoretical derivation, algorithm design for dispersed fringe sensing based on Fourier transform, open-loop and close-loop experiments are carried out with the Fizeau interference experimental facilities in our lab. In the open-loop experiment, we collect many dispersed fringe images with different piston errors and research on the relationship between peak displacements in the spectrogram and piston errors, the results show a good linear relationship. In the close-loop experiment, we make close-loop control for the piston error with real-time calculation results and piston error compensating elements, the results show that the system remains at the initial interference state with extra perturbation.