An 11-frame phase shifting algorithm in lateral shearing interferometry.

In order to eliminate zeroth order effect and to make the phase shifting algorithm insensitive to phase shifting error, an 11-frame phase shifting algorithm is proposed in this paper. The analytical expression of phase-restoration error function is derived. The principle of phase shifting error compensation and the capability of suppressing zeroth order effect are explained, in comparison of existing algorithm. The analytical results show that this algorithm's phase-restoration error is proportional to sine of double shearing phase and to biquadratic of phase shifting error. Finally, we generate the interference patterns of 11-frame algorithm and existing algorithm, restore the shearing phases and calculate the phase-restoration errors by simulations. The simulation results verify the theoretical analyses.

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