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The memory effect in the form of hysteresis has been detected in the measured dependence of the intensity of the photon echo in YLiF4 and LuLiF4 samples with Er3+ impurity ions on the orientation, strength, and variation direction of the magnetic field. The prehistory of the location of a sample in the magnetic field with a certain direction and strength is written and stored for no less than 6 h at a temperature of 2 K. The effect crucially depends on the orientation of the optical axis of the sample with respect to the external magnetic field. [ABSTRACT FROM AUTHOR]

The memory effect in the form of hysteresis has been detected in the measured dependence of the intensity of the photon echo in YLiF4 and LuLiF4 samples with Er3+ impurity ions on the orientation, strength, and variation direction of the magnetic field. The prehistory of the location of a sample in the magnetic field with a certain direction and strength is written and stored for no less than 6 h at a temperature of 2 K. The effect crucially depends on the orientation of the optical axis of the sample with respect to the external magnetic field. [ABSTRACT FROM AUTHOR]

Abstract: The pseudo-Stark shift in the optical frequency of the 4F9/2-4I15/2 transition of an Er3+ ion in a Y2SiO5 matrix under the action of a weak pulsed electric field is measured from changes in the amplitude and temporal shape of the photon echo. [ABSTRACT FROM AUTHOR]

The energy flux of phonons produced due to the nonradiative laser-induced transitions of Ho3+ impurity ions in forsterite from the 5F5 states has been measured using a superconductor bolometer at a temperature of 2 K. The dependence of the flux on the laser wavelength, the time elapsed after the action of a laser pulse, and the phonon propagation path length is analyzed. It is found that the excitation of Ho3+ to some states leads to the diffusive propagation of emitted phonons in the spontaneous frequency decay mode (quasidiffusive mode of propagation): the time of arrival of a phonon pulse is almost a linear function of the path length, but it is several times longer than the longest ballistic time of flight (for transverse phonons). The diffusion coefficient and the nonradiative relaxation time are determined from the best fit to the experiment. © 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]

A rather simple method is used to simultaneously detect both optical absorption spectra and excited-state nonradiative transitions in 0.03 and 0.16 at. % ruby at temperature 2 K. The technique utilizes a time-resolved bolometer detection of phonons generated by the excited-state nonradiative relaxation following optical excitation with a pulsed tunable dye laser. The observed excitation spectra of phonons coincide well with currently known absorption spectra of both chromium single ions and pairs of the nearest neighbors. For the first time, the fast (≤5 μs) resonant energy transfer from single chromium ions to the fourth nearest neighbors is observed directly. New strongly perturbed Cr-single-ion sites are observed. © 2003 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]