All optical image processing and pattern recognition apparatus using stimulated photon echoes

An all optical image processing and pattern recognition apparatus using stimulated photon echoes comprising:

• a stimulated photon echo medium having an inhomogeneous broadening line shape function;
• first incident means for launching a first optical pulse train including two or more optical pulses into said photon echo medium;
• second incident means for launching a second optical pulse into said photon echo medium from a direction different from the incident direction of said first optical pulse train in the coherence-decay time of said photon echo medium after the incidence of said first optical pulse train;
• third incident means for launching a third optical pulse into said photon echo medium in the population-decay time of said photon echo medium after the incidence of said second optical pulse, said population-decay time being defined as time during which said medium returns to its thermal equilibrium state from its excited state;
• and
• optical detecting means for detecting photon echoes emitted from said photon echo medium,
• wherein said first optical pulse train includes a plurality of pieces of image information.