Three -dimensional phase measurement of transparent gas by high -speed digital holographic tomography system

A high-speed digital holographic tomography system based on off-axis multiplexed recording is proposed for fast three-dimensional (3-D) phase measurements of transparent gasses. Object beams pass through the object at 0, 45, 90, and 135 degrees and interfere with the reference beam to form a hologram that is recorded by a single camera. The phase information of each optical path is reconstructed by the Fresnel diffraction integral calculation, and then the 3-D phase information of the object can be obtained by the simple back-projection algorithm. The recording speed of the system depends entirely on the frame rate of the camera. In the experiments, we successfully measured the 3-D phase information of an asymmetric gas flow with the proposed system at 65 frames per second.

Automated summary

A high-speed digital holographic tomography system based on off-axis multiplexed recording is introduced for fast 3D phase measurements of transparent gasses. By using object beams at various angles and interfering with the reference beam, holograms are recorded and phase information is reconstructed to obtain the 3D phase information of the object by back-projection algorithm. The system achieved a measurement speed of 65 frames per second for an asymmetric gas flow in the experiments.