AUGER UP-CONVERSION LOSSES IN ND-DOPED LASER GLASSES

We have measured the Auger upconversion constant, gamma, of Nd3+ ions in phosphate, silicate, and fluoride glasses. The Auger process involv es two Nd3+ ions initially in the 4F3/2 metastable state that interact such that one ion is promoted to a higher lying state, while the othe r is forced to the 4I(J) levels of the ground state. gamma values rang ing from 2.6 to 8.1 x 10(-17) cm3 s-1 were measured, depending on the host medium and neodymium concentration. The product of the emission l ifetime and the Auger coefficient was found to be in the range of gamm atau = (1-2) x 10(-20) cm3 for the materials investigated. This sugges ts that Auger upconversion is an important problem for excited state d ensities approaching (5-10)x10(19) cm-3.