HOLOGRAPHIC SCHLIEREN METHOD

摘要

A double exposed hologram is reconstructed by the schlieren method. The hologram of a disturbed and undisturbed scene is twice exposed so that the reference beam forms a different angle with the recording material for each exposure. The recording material has a non-linear characteristic so that intermodulation products of the fringes are generated. The hologram is reconstructed with a reconstruction reference beam. All but a selected diffraction order are eliminated and the selected order is viewed with a knife edge to make visible the phase change of the scene recorded. The reconstruction reference beam must be substantially free of aberrations; otherwise there are no such restrictions on the recording optical elements.