Anti-disturbance phase-shifting interferometry method time-and-frequency-domain

Because interferometry is highly sensitive to disturbance such as vibration and air flow, a time-and-frequency domain (TFD) interferometry is proposed. A large number of continuous phase-shifting interferograms are captured. A distorted series of phase variety during fringe capturing is obtained through wide bandwidth filter to the spectrum of intensity series from a particular pixel, and then a linear statistic of it gives the measuring result of initial phase. With a large enough number of frames, the linear statistic efficiently reduces random noises to zero. And influences introduced by other non-random disturbances are astringed into a value which is independent of the index of pixels and therefore does not influence the shape of the whole wavefront. A simulation confirms the feasibility of the TFD method, and an experiment is carried out applying TFD method in a mechanical phase-shifting interferometric system fixed in a normal laboratory environment. The result prettily matches that from a FISBA interferometer, which verifies the anti-noise ability of TFD method.