CR3-]ND3+ ENERGY-TRANSFER AND ND3+ LASER ACTION STUDIES OF LA(3)GA(5)SIO(1)4-CR3+ND3+ CO-DOPED CRYSTAL()

Energy transfer between Cr3+ and Nd3+ ions has been investigated in th e 4.2-300-K temperature range by using steady-state and site-selective time-resolved laser spectroscopy, Radiative and nonradiative energy t ransfer has been studied from the time-resolved emission spectra and t he donor fluorescence decays, The transfer efficiency was calculated a s a function of temperature by using the Cr3+ lifetimes of the single doped and co-doped samples, Laser experiments were carried out in a di ffusive cavity by pumping a co-doped rod 54 mm long and 5 mm in diamet er with Xenon flashlamps. The laser spectral emission shows a complex structure which varies as a function of pump energy. The temporal evol ution of the laser spectrum is discussed in terms of a simple four-lev el spectral rate-equation laser model which takes into account the exi stence of two main broad Nd3+ site distributions with a large spectral overlap.