| 摘要 |
The apparatus performs phase imaging interferometry on a test medium with spatially varying optical length. The apparatus uses a polarization based phase shift element in either the probe or reference arm of the interferometer to simultaneously generate both the conventional in-phase spatial interferogram of the test medium, and a quadrature interferogram which is ninety degrees out of phase with the conventional interferogram at all image positions, allowing a reconstruction of the test medium's interferometric phase image over 0 to 2 pi radians. In contrast to the prior art, the present invention accomplishes the phase shifting operation in a single interferometer stage, using a polarizing beam splitter which accomplishes polarized seggregation of the interferometer output beam. The apparatus has high resistance to vibrations, instability and misalignment errors.
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