4-DIMENSIONAL OPTICAL ECHO HOLOGRAPHY

We theoretically investigate the formation of photon-echo signals in a gas under conditions when the velocities of gas particles are compara ble with the speed of light. Relativistic corrections to spatial phase -matching conditions and the moment of generation of an echo response in the time domain are derived for the signals of stimulated and phase -conjugate photon echo. The specific features of echo-hologram recordi ng on a flow of relativistic particles are considered.