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

• Published in: Optics and lasers in engineering 2023-09, Vol.168, p.107656, Article 107656
• Main Authors: Xia, Peng, Ri, Shien
• Format: Article
• Language: English
• Subjects: High-speed 3D imaging; Holographic tomography; Off-axis multiplexing; Phase measurement
• ISSN: 0143-8166; 1873-0302
• DOI: 10.1016/j.optlaseng.2023.107656

•A high-speed digital holographic tomography system is developed.•Interference information from four optical paths is recorded in a single hologram based on off-axis multiplexing.•3-D dynamic phase measurement of an asymmetric gas flow is achieved. 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° 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.