Three-dimensional imaging of distribution of refractive index by parallel phase-shifting digital holography using...

Although digital holography is a powerful technique obtaining a phase image of a transparent object, the image reconstructed by the technique merely expresses phase distribution of the light wave after transmitting through the object. Phase variation of inside of the object is difficult to be obtained. Then, we applied Abel inversion method to the high-speed phase image of a dynamic transparent object assumed axially symmetric. The phase is accurately recorded by phase-shifting method. We experimentally recorded transparent dynamic gas flow, assumed axially symmetric along the direction in which gas flowed, at 3,000 frame/s and reconstructed motion picture of 3D distribution of the refractive index of the gas from the high-speed phase motion picture obtained by parallel phase-shifting digital holography.