Photon echo studies of LaF3:Pr3+ nanocrystals in glass

Optical dephasing of rare-earth ions doped in LaF3 nanocrystals embedded in the glass ceramics is studied by the two-pulse photon echo. It is found that the dephasing time, T2, is 30–50 ns for 3H4–3P0 transition of Pr3+-doped samples that has a nanoparticle size of 30–40 nm. A quasilinear temperature dependence is observed and a zero-temperature residual line width is also obtained as seen by spectral hole burning. Possible mechanisms that dominate the dephasing process and that contribute to the spectral diffusion (slower process) are discussed by comparing the echo results with those of the spectral hole burning.