Dynamics of broadband accumulated spectral gratings in Tm ^3+ :YAG

Abstract

High-bandwidth accumulated spectral gratings are experimentally studied in Tm3+:YAG by the stimulated-photon-echo technique with a mode-locked picosecond Ti:sapphire laser system. The experimental results show that the spectral grating builds up and decays on the time scale of the metastable-state lifetime (∼10 ms), provided that the time interval of accumulating shots is of the order of the excited-state lifetime (800 µs). An echo efficiency of the order of 0.1% was achieved with pulse intensities 2 orders of magnitude less than those needed for a single-shot process. These results fit well an analytic solution of the Bloch equations and a three-level system relaxation model.