THEORY OF SINGLE-PHOTON ECHO (SP-ECHO) AND THE POSSIBILITY OF ITS EXPERIMENTAL-STUDY IN THE GAMMA-REGION

The single-photon echo (SP-echo) effect is predicted to appear in the case of three-level medium excitation by means of a single photon prop agating to the medium along two optical paths with a mutual time delay surpassing the temporal duration of the photon wave packet. The quant um electrodynamical theory describing this interaction is presented an d the S-matrix of the field is shown for infinite time (t = infinity). Using the S-matrix approach, physical properties of the scattering fi eld are studied. Hence, it is shown that the field has an echo signal at the omega(32)(0) carrier frequency. It has been shown that the echo signal exists only in the field amplitude while being absent in its i ntensity behaviour. Thus, SP-echo is an interference effect and is not influenced by the energy irradiation. The problems of SP-echo detecti on in the gamma-region (where special generation difficulties appear) are discussed. The influence of the additional detection of the omega( 21)(0) frequency field on the echo signal has been shown. A special ca se is the EPR-paradox which can appear within the echo phenomenon.