Cr/sup 3+//spl rarr/Nd/sup 3+/ energy transfer and Nd/sup 3+/ laser action studies of La/sub 3/Ga/sub 5/SiO/sub 14/:Cr/sup 3+/,Nd/sup 3+/ co-doped crystal

Energy transfer between Cr/sup 3+/ and Nd/sup 3+/ ions has been investigated in the 4.2-300-K temperature range by using steady-state and site-selective time-resolved laser spectroscopy. Radiative and nonradiative energy transfer has been studied from the time-resolved emission spectra and the donor fluorescence decays. The transfer efficiency was calculated as a function of temperature by using the Cr/sup 3+/ lifetimes of the single doped and co-doped samples. Laser experiments were carried out in a diffusive cavity by pumping a co-doped rod 54 mm long and 5 mm in diameter with xenon flashlamps. The laser spectral emission shows a complex structure which varies as a function of pump energy. The temporal evolution of the laser spectrum is discussed in terms of a simple four-level spectral rate-equation laser model which takes into account the existence of two main broad Nd/sup 3+/ site distributions with a large spectral overlap.