This paper concerns itself with the investigation of a method for solving the longstanding problem of longitudinal image distortion encountered in longwave (microwave or acoustic) holography that has so far prevented the exploitation of the three-dimensional imaging capability of holography. A scheme for real-time, distortionless image reconstruction from longwave holograms that has the potential of yielding three-dimensional images which can be viewed with the unaided eye is described. The scheme is based on combining the operations of a semiconductor spatial microwave modulator with that of a plasma chamber in which visualization is due to light emission caused by microwave-induced enhanced ionization and luminosity in a weakly ionized r.f. plasma. The scheme has the potential advantage of being implementable in real time when a light value is added. Relatively reasonable level millimeter microwave reconstruction power of .6 watts average is shown to be sufficient for the reconstruction of a three-dimensional image consisting of 1000 resolvable points using commercially available millimeter wave sources, assuming that the local enhanced luminosity is caused by a doubling of the ionization rate in a low frequency r.f. discharge plasma.
N. H. Farhat,
A. K. Chua,
"Three-Dimensional Image Reconstruction from Longwave Holograms A Feasibility Study," Optical Engineering 14(3), 143200 (1 June 1975). https://doi.org/10.1117/12.7971866