VIBRATION MEASURING APPARATUS BY DOUBLE PULSE LASER HOLOGRAPHY

摘要

PURPOSE:To easily determine a vibration direction, by a method wherein a part of a reflected light from a matter to be measured is directly incident on a part of a dry plate A and the other part thereof is incident on a part of a dry plate B through a light path length altering means. CONSTITUTION:A part of the light from matter 2 to be measured directly irradiates a part A of a dry plate 3. The reference light obtained from a flat mirror 5b interferes with the light from the matter 2 at a part A of the dry plate 3 and the luminous intensity distributions due to interference are doubly recorded by pulse laser beams emitted two times. The reference light obtained from the flat mirror 5b interferes with the light from the matter 2 obtained by a fixed flat mirror 7b at a part B of the dry plate 3 and luminous intensity distributions due to interference are doubly recorded by pulse laser beams emitted two times. If the dry plate 3 is developed to form a hologram to observe a regenerated image, the vibration distribution of the matter to be measured can be measured from the interference fringe pattern thereof. An interference fringe generated by the vibration displacement and the change in the light path length of the light from the matter to be measured is confirmed at a spatial position different from the matter to be measured from the B-part of the hologram and a vibration direction can be easily judged by changing a visual point.