Laser-Induced Grating Measurements of Energy Migration in Tm,Ho:YAG

摘要

We report, what is to our knowledge the first direct measurement of spatialenergy migration among the Tm3+ ions in a Tm,Ho:YAG crystal at room temperature. Four-wave mixing techniques were used to establish and probe transient laser-induced population gratings in the Tm3+ ions. The grating decay rate was measured as a function of the grating spacing. The results show the presence of spatial energy migration among the Tm3+ ions, and the diffusion coefficient of this process was measured to be 4 X 10 to the -7th power/sq cm/s for a sample containing 8.3 X 10 to the 20 power/cc Tm3+ ions. Laser-induced grating(LIG) spectroscopy has been shown to be an important method of investigating energy transfer among ions in solids. It is the only experimental technique that can directly measure resonant interactions that result in spatial energy migration without spectral transfer.