The simultaneous suppression of phase shift error and harmonics in the phase shifting interferometry using carrier squeezing interferometry

The phase shift errors and the harmonics are the most common types of errors in the phase shifting interferometry. Although there are many suppression techniques for these two errors, it is hard to suppress them simultaneously. In this paper the carrier squeezing interferometry is used to solve this problem, where the data of phase shifting interferograms with linear carrier are re-arranged to acquire a spatial–temporal fringes image. In the frequency domain of the image the lobes of harmonics and phase shift errors and the lobe of the phase are separated, so the correct phase can be extracted by filtering. The algorithm is validated by both simulations and the experiments, with the phase retrieving accuracy greater than λ/400 and λ/200 (RMS value), respectively. The spatial uniform phase shift errors and harmonics can be suppressed by this method, using only four phase shifting interferograms.