Spectrally controlled interference of picosecond time-and-space-domain holograms.

We show that two superimposed time-and-space-domain holograms in a persistent spectral hole-burning material can produce destructive interference, even if the path-length difference of the writing beams is constant. The cancellation of the amplitudes in the 21 diffraction order occurs when the two holograms have specially chosen spectral envelopes that represent a pair of complementary functions. By controlling the spectrum of the holograms we are able to perform coherent subtraction and addition of images.