METHOD OF RECORDING OF TWO-EXPOSITION HOLOGRAPHIC INTERFEROGRAM Russian patent published in 1994 - IPC

FIELD: instrument engineering. SUBSTANCE: when recording two-exposition holographic interferogram onto photothermoplastic material, any hologram when being recorded is exposed, loaded and heated at the material simultaneously in time interval being sufficient for transition of object under test from one condition to another one. Any exposure is made with delay relatively the load. The first hologram is erased before the second exposure and load. Time τ₁ of the first exposure delay relatively the start point of the first load is chosen according to maximal differential efficiency of the first hologram. Delay times t₁ и t₂ of relief-forming are determined preliminary when recording the first hologram; these times are used at subsequent restoration of the hologram when using residual memory. The second exposure is carried out with delay τ₂≅ τ₁-(t₁-t₂) in relation to the start point of the second load. EFFECT: improved efficiency; improved quality. 2 dwg