Spectroscopic investigations of the 4f5d energy levels of Pr3+ in fluoridecrystals by excited-state absorption and two-step excitation measurements

Excited-state absorption spectra obtained by a pulsed pump-probe technique specially designed for the near-UV spectral domain were recorded in three P r3+-doped fluoride crystals (KY3F10, LiYF4, and BaY2F8). These excited-stat e absorption spectra correspond to optical transitions from the P-3(0) or t he D-1(2) metastable levels of the 4f(2) configuration up to the first ener gy levels of the 4f5d electronic configuration. The position, the anisotrop ic behavior, and the line shape of the observed excited-state absorption ba nds are discussed and compared with ground-state absorption (from level H-3 (4)) or direct excitation spectra available in the literature. Subsequently , two-step excitation into the 4f5d high-lying energy levels of Pr-3 by mea ns of P-3(0) and D-1(2) is shown to be an efficient way to produce broadban d UV fluorescence by use of pump beams in the blue and the near UV. (C) 199 9 Optical Society of America [S0740-3224(99)00712-2].