ANALYSIS ON THE TM3-ZIRCO-FLUORIDE GLASS FOR EFFICIENT 2-MU-M LASING(, HO3+ CONCENTRATIONS IN ALUMINO)

The dependence of gain coefficients for a Tm3+, Ho3+ co-doped alumino- zirco-fluoride glass on Ho3+ concentration under a 0.79 mu m pumping i s described. The calculation of the gain coefficients is made with the upconversion rate constant from the lower coupled (Tm3+3F4, Ho3+5I7) level to the upper coupled (Tm3+3H5, Ho3+5I6) level. The gain is deter mined by measuring absorption coefficients and their appropriate compa rison with a simple Tm3+-Ho3+ energy transfer model. The Tm3+, Ho3+ co ncentrations suitable for eyesafe laser applications at two micrometer s are determined as a function of pumping intensity.