TIME-AVERAGED HOLOGRAPHY WITH TRIANGULAR PHASE MODULATION OF REFERENCE WAVE

It is shown that the large differences of the peak fringe intensities in the reconstruction of time-averaged holograms may be reduced by synchronous triangular phase modulation of the reference wave. As a by-product, portions of the object vibrating in the same phase are revealed. Optical noise in the reconstruction is low so that the useful amplitude range in vibration analysis is significantly extended by the method described. © 1969 The American Institute of Physics.