NEW CHANNELS OF PHOTON-ECHO RELAXATION IN Y2SIO5-PR3-PR3+ CRYSTALS( AND LAF3)

Experimental results on the investigation of low-temperature optical a bsorption spectra and temperature dependence of the photon echo (PE) a mplitude signal in Y2SiO5:Pr3+ and LaF3:Pr3+ crystals at the transitio n H-3(4)(O) - P-3(0) of the Pr3+ ion are presented. It is shown that a dditional relaxation channels exist for PE in addition to the known ph onon mechanisms. This is associated in a LaF3:Pr3+ crystal with the te mperature variation of dipole moment at the Pr3+ ion transition. In a Y2SiO5:Pr3+ crystal, this is due to the thermally activated transition s for the Pr3+ ion between nonequivalent positions in the crystal latt ice. (C) 1997 American Institute of Physics.