Anti-Vibration Capability of Time-Frequency Domain Wave Front Testing Method

Because of its high sensitivity to vibrations, the phase-shifting interferometry system is often quite complicated. A time-frequency domain (TFD) method is proposed in this research, which could make the system in compact for field testing. A large number of interferograms are captured. For the particular pixels in interferograms, a series of distorted phase is obtained through wide bandwidth filtering and reverse Fourier transform of the spectrum of intensity series. Then the linear fit method is used. For a large enough number of interferograms, a linear fit of the distorted phase efficiently could reduce random noises towards zero, and astringe other nonrandom disturbances into a nonzero data which is independent to index of pixels and therefore dose not influence the shape of the whole wave front. Under a precise of λ/100, the maximum amplitude-frequency product (AFP) of anti-vibration capability was obtained by simulation, which verifies the feasibility of the method and lays the foundation for application of the method in compact system.